<?xml version="1.0" encoding="us-ascii"?>
<!-- DFS ActiveDisclosure(SM) XBRL Linkbase Document - http://www.dfsco.com/financial-services/ -->
<!-- Creation Date      : 2017-02-28T15:37:21.3103667+00:00 -->
<!-- Version            : 2.4.1.13 -->
<!-- Package ID         : 9B2393E473B9FD6F2230951F1789637B-0001668397-001612 -->
<!-- Copyright (c) 2017 Donnelley Financial, LLC. All Rights Reserved. -->
<linkbase xmlns="http://www.xbrl.org/2003/linkbase" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xbrldt="http://xbrl.org/2005/xbrldt" xsi:schemaLocation="http://www.xbrl.org/2003/linkbase http://www.xbrl.org/2003/xbrl-linkbase-2003-12-31.xsd">
  <arcroleRef xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#all" arcroleURI="http://xbrl.org/int/dim/arcrole/all" />
  <arcroleRef xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#dimension-default" arcroleURI="http://xbrl.org/int/dim/arcrole/dimension-default" />
  <arcroleRef xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#dimension-domain" arcroleURI="http://xbrl.org/int/dim/arcrole/dimension-domain" />
  <arcroleRef xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#domain-member" arcroleURI="http://xbrl.org/int/dim/arcrole/domain-member" />
  <arcroleRef xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#hypercube-dimension" arcroleURI="http://xbrl.org/int/dim/arcrole/hypercube-dimension" />
  <roleRef xlink:type="simple" xlink:href="medp-20161231.xsd#TemplateLink" roleURI="http://www.medpace.com/20161231/role/TemplateLink" />
  <roleRef roleURI="http://www.medpace.com/20161231/taxonomy/role/StatementCONSOLIDATEDSTATEMENTSOFOPERATIONS" xlink:href="medp-20161231.xsd#Role_StatementCONSOLIDATEDSTATEMENTSOFOPERATIONS" xlink:type="simple" />
  <definitionLink xlink:type="extended" xlink:role="http://www.medpace.com/20161231/taxonomy/role/StatementCONSOLIDATEDSTATEMENTSOFOPERATIONS">
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding" xlink:type="locator" xlink:label="us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_WeightedAverageNumberOfSharesOutstandingBasic" xlink:type="locator" xlink:label="us-gaap_WeightedAverageNumberOfSharesOutstandingBasic" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_WeightedAverageNumberOfSharesOutstandingAbstract" xlink:type="locator" xlink:label="us-gaap_WeightedAverageNumberOfSharesOutstandingAbstract" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_EarningsPerShareDiluted" xlink:type="locator" xlink:label="us-gaap_EarningsPerShareDiluted" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_EarningsPerShareBasic" xlink:type="locator" xlink:label="us-gaap_EarningsPerShareBasic" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_EarningsPerShareAbstract" xlink:type="locator" xlink:label="us-gaap_EarningsPerShareAbstract" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_NetIncomeLoss" xlink:type="locator" xlink:label="us-gaap_NetIncomeLoss" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_IncomeTaxExpenseBenefit" xlink:type="locator" xlink:label="us-gaap_IncomeTaxExpenseBenefit" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest" xlink:type="locator" xlink:label="us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_NonoperatingIncomeExpense" xlink:type="locator" xlink:label="us-gaap_NonoperatingIncomeExpense" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_InterestIncomeExpenseNonoperatingNet" xlink:type="locator" xlink:label="us-gaap_InterestIncomeExpenseNonoperatingNet" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_OtherNonoperatingIncomeExpense" xlink:type="locator" xlink:label="us-gaap_OtherNonoperatingIncomeExpense" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_GainsLossesOnExtinguishmentOfDebt" xlink:type="locator" xlink:label="us-gaap_GainsLossesOnExtinguishmentOfDebt" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_OtherIncomeAndExpensesAbstract" xlink:type="locator" xlink:label="us-gaap_OtherIncomeAndExpensesAbstract" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_OperatingIncomeLoss" xlink:type="locator" xlink:label="us-gaap_OperatingIncomeLoss" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_CostsAndExpenses" xlink:type="locator" xlink:label="us-gaap_CostsAndExpenses" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_AmortizationOfIntangibleAssets" xlink:type="locator" xlink:label="us-gaap_AmortizationOfIntangibleAssets" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_Depreciation" xlink:type="locator" xlink:label="us-gaap_Depreciation" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_GoodwillImpairmentLoss" xlink:type="locator" xlink:label="us-gaap_GoodwillImpairmentLoss" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_BusinessCombinationIntegrationRelatedCosts" xlink:type="locator" xlink:label="us-gaap_BusinessCombinationIntegrationRelatedCosts" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_SellingGeneralAndAdministrativeExpense" xlink:type="locator" xlink:label="us-gaap_SellingGeneralAndAdministrativeExpense" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_CostOfReimbursableExpense" xlink:type="locator" xlink:label="us-gaap_CostOfReimbursableExpense" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_CostOfServicesExcludingDepreciationDepletionAndAmortization" xlink:type="locator" xlink:label="us-gaap_CostOfServicesExcludingDepreciationDepletionAndAmortization" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_OperatingExpensesAbstract" xlink:type="locator" xlink:label="us-gaap_OperatingExpensesAbstract" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_SalesRevenueNet" xlink:type="locator" xlink:label="us-gaap_SalesRevenueNet" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ReimbursementRevenue" xlink:type="locator" xlink:label="us-gaap_ReimbursementRevenue" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_SalesRevenueServicesNet" xlink:type="locator" xlink:label="us-gaap_SalesRevenueServicesNet" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_RevenuesAbstract" xlink:type="locator" xlink:label="us-gaap_RevenuesAbstract" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_PredecessorMember" xlink:type="locator" xlink:label="us-gaap_PredecessorMember" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ScenarioUnspecifiedDomain" xlink:type="locator" xlink:label="us-gaap_ScenarioUnspecifiedDomain_2" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ScenarioUnspecifiedDomain" xlink:type="locator" xlink:label="us-gaap_ScenarioUnspecifiedDomain" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_StatementScenarioAxis" xlink:type="locator" xlink:label="us-gaap_StatementScenarioAxis" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_StatementTable" xlink:type="locator" xlink:label="us-gaap_StatementTable" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_StatementLineItems" xlink:type="locator" xlink:label="us-gaap_StatementLineItems" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="us-gaap_StatementLineItems" xlink:to="us-gaap_StatementTable" order="10190.00" priority="2" use="optional" xbrldt:contextElement="segment" xbrldt:closed="true" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="us-gaap_StatementTable" xlink:to="us-gaap_StatementScenarioAxis" order="10220.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="us-gaap_StatementScenarioAxis" xlink:to="us-gaap_ScenarioUnspecifiedDomain_2" order="10240.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_StatementScenarioAxis" xlink:to="us-gaap_ScenarioUnspecifiedDomain" order="10240.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ScenarioUnspecifiedDomain" xlink:to="us-gaap_PredecessorMember" order="10260.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_StatementLineItems" xlink:to="us-gaap_RevenuesAbstract" order="10290.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_RevenuesAbstract" xlink:to="us-gaap_SalesRevenueServicesNet" order="10450.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_RevenuesAbstract" xlink:to="us-gaap_ReimbursementRevenue" order="10610.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_RevenuesAbstract" xlink:to="us-gaap_SalesRevenueNet" order="10770.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_StatementLineItems" xlink:to="us-gaap_OperatingExpensesAbstract" order="10930.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_OperatingExpensesAbstract" xlink:to="us-gaap_CostOfServicesExcludingDepreciationDepletionAndAmortization" order="11090.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_OperatingExpensesAbstract" xlink:to="us-gaap_CostOfReimbursableExpense" order="11250.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_OperatingExpensesAbstract" xlink:to="us-gaap_SellingGeneralAndAdministrativeExpense" order="11410.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_OperatingExpensesAbstract" xlink:to="us-gaap_BusinessCombinationIntegrationRelatedCosts" order="11570.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_OperatingExpensesAbstract" xlink:to="us-gaap_GoodwillImpairmentLoss" order="11730.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_OperatingExpensesAbstract" xlink:to="us-gaap_Depreciation" order="11890.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_OperatingExpensesAbstract" xlink:to="us-gaap_AmortizationOfIntangibleAssets" order="12050.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_OperatingExpensesAbstract" xlink:to="us-gaap_CostsAndExpenses" order="12210.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_StatementLineItems" xlink:to="us-gaap_OperatingIncomeLoss" order="12370.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_StatementLineItems" xlink:to="us-gaap_OtherIncomeAndExpensesAbstract" order="12530.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_OtherIncomeAndExpensesAbstract" xlink:to="us-gaap_GainsLossesOnExtinguishmentOfDebt" order="12690.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_OtherIncomeAndExpensesAbstract" xlink:to="us-gaap_OtherNonoperatingIncomeExpense" order="12850.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_OtherIncomeAndExpensesAbstract" xlink:to="us-gaap_InterestIncomeExpenseNonoperatingNet" order="13010.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_OtherIncomeAndExpensesAbstract" xlink:to="us-gaap_NonoperatingIncomeExpense" order="13170.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_OtherIncomeAndExpensesAbstract" xlink:to="us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest" order="13330.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_OtherIncomeAndExpensesAbstract" xlink:to="us-gaap_IncomeTaxExpenseBenefit" order="13490.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_OtherIncomeAndExpensesAbstract" xlink:to="us-gaap_NetIncomeLoss" order="13650.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_StatementLineItems" xlink:to="us-gaap_EarningsPerShareAbstract" order="13810.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_EarningsPerShareAbstract" xlink:to="us-gaap_EarningsPerShareBasic" order="13970.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_EarningsPerShareAbstract" xlink:to="us-gaap_EarningsPerShareDiluted" order="14130.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_StatementLineItems" xlink:to="us-gaap_WeightedAverageNumberOfSharesOutstandingAbstract" order="14290.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_WeightedAverageNumberOfSharesOutstandingAbstract" xlink:to="us-gaap_WeightedAverageNumberOfSharesOutstandingBasic" order="14450.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_WeightedAverageNumberOfSharesOutstandingAbstract" xlink:to="us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding" order="14610.00" priority="2" use="optional" />
  </definitionLink>
  <roleRef roleURI="http://www.medpace.com/20161231/taxonomy/role/StatementCONSOLIDATEDSTATEMENTSOFOPERATIONSParenthetical" xlink:href="medp-20161231.xsd#Role_StatementCONSOLIDATEDSTATEMENTSOFOPERATIONSParenthetical" xlink:type="simple" />
  <definitionLink xlink:type="extended" xlink:role="http://www.medpace.com/20161231/taxonomy/role/StatementCONSOLIDATEDSTATEMENTSOFOPERATIONSParenthetical">
    <loc xlink:href="medp-20161231.xsd#medp_ReimbursedOutOfPocketExpensesWithRelatedParties" xlink:type="locator" xlink:label="medp_ReimbursedOutOfPocketExpensesWithRelatedParties" />
    <loc xlink:href="medp-20161231.xsd#medp_ReimbursedOutOfPocketRevenueWithRelatedParties" xlink:type="locator" xlink:label="medp_ReimbursedOutOfPocketRevenueWithRelatedParties" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_RevenueFromRelatedParties" xlink:type="locator" xlink:label="us-gaap_RevenueFromRelatedParties" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_PredecessorMember" xlink:type="locator" xlink:label="us-gaap_PredecessorMember" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ScenarioUnspecifiedDomain" xlink:type="locator" xlink:label="us-gaap_ScenarioUnspecifiedDomain" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_StatementScenarioAxis" xlink:type="locator" xlink:label="us-gaap_StatementScenarioAxis" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_StatementTable" xlink:type="locator" xlink:label="us-gaap_StatementTable" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_StatementLineItems" xlink:type="locator" xlink:label="us-gaap_StatementLineItems" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="us-gaap_StatementLineItems" xlink:to="us-gaap_StatementTable" order="10010.00" priority="2" use="optional" xbrldt:contextElement="segment" xbrldt:closed="true" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="us-gaap_StatementTable" xlink:to="us-gaap_StatementScenarioAxis" order="10040.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_StatementScenarioAxis" xlink:to="us-gaap_ScenarioUnspecifiedDomain" order="10060.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ScenarioUnspecifiedDomain" xlink:to="us-gaap_PredecessorMember" order="10080.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_StatementLineItems" xlink:to="us-gaap_RevenueFromRelatedParties" order="10110.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_StatementLineItems" xlink:to="medp_ReimbursedOutOfPocketRevenueWithRelatedParties" order="10270.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_StatementLineItems" xlink:to="medp_ReimbursedOutOfPocketExpensesWithRelatedParties" order="10430.00" priority="2" use="optional" />
  </definitionLink>
  <roleRef roleURI="http://www.medpace.com/20161231/taxonomy/role/StatementCONSOLIDATEDSTATEMENTSOFCOMPREHENSIVEINCOMELOSS" xlink:href="medp-20161231.xsd#Role_StatementCONSOLIDATEDSTATEMENTSOFCOMPREHENSIVEINCOMELOSS" xlink:type="simple" />
  <definitionLink xlink:type="extended" xlink:role="http://www.medpace.com/20161231/taxonomy/role/StatementCONSOLIDATEDSTATEMENTSOFCOMPREHENSIVEINCOMELOSS">
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ComprehensiveIncomeNetOfTax" xlink:type="locator" xlink:label="us-gaap_ComprehensiveIncomeNetOfTax" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_OtherComprehensiveIncomeLossForeignCurrencyTransactionAndTranslationAdjustmentNetOfTax" xlink:type="locator" xlink:label="us-gaap_OtherComprehensiveIncomeLossForeignCurrencyTransactionAndTranslationAdjustmentNetOfTax" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_OtherComprehensiveIncomeLossNetOfTaxPeriodIncreaseDecreaseAbstract" xlink:type="locator" xlink:label="us-gaap_OtherComprehensiveIncomeLossNetOfTaxPeriodIncreaseDecreaseAbstract" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_NetIncomeLoss" xlink:type="locator" xlink:label="us-gaap_NetIncomeLoss" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_PredecessorMember" xlink:type="locator" xlink:label="us-gaap_PredecessorMember" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ScenarioUnspecifiedDomain" xlink:type="locator" xlink:label="us-gaap_ScenarioUnspecifiedDomain" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_StatementScenarioAxis" xlink:type="locator" xlink:label="us-gaap_StatementScenarioAxis" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_StatementTable" xlink:type="locator" xlink:label="us-gaap_StatementTable" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_StatementLineItems" xlink:type="locator" xlink:label="us-gaap_StatementLineItems" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="us-gaap_StatementLineItems" xlink:to="us-gaap_StatementTable" order="10030.00" priority="2" use="optional" xbrldt:contextElement="segment" xbrldt:closed="true" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="us-gaap_StatementTable" xlink:to="us-gaap_StatementScenarioAxis" order="10060.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_StatementScenarioAxis" xlink:to="us-gaap_ScenarioUnspecifiedDomain" order="10080.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ScenarioUnspecifiedDomain" xlink:to="us-gaap_PredecessorMember" order="10100.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_StatementLineItems" xlink:to="us-gaap_NetIncomeLoss" order="10130.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_StatementLineItems" xlink:to="us-gaap_OtherComprehensiveIncomeLossNetOfTaxPeriodIncreaseDecreaseAbstract" order="10210.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_StatementLineItems" xlink:to="us-gaap_OtherComprehensiveIncomeLossForeignCurrencyTransactionAndTranslationAdjustmentNetOfTax" order="10370.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_StatementLineItems" xlink:to="us-gaap_ComprehensiveIncomeNetOfTax" order="10530.00" priority="2" use="optional" />
  </definitionLink>
  <roleRef roleURI="http://www.medpace.com/20161231/taxonomy/role/StatementCONSOLIDATEDSTATEMENTSOFSHAREHOLDERSEQUITY" xlink:href="medp-20161231.xsd#Role_StatementCONSOLIDATEDSTATEMENTSOFSHAREHOLDERSEQUITY" xlink:type="simple" />
  <definitionLink xlink:type="extended" xlink:role="http://www.medpace.com/20161231/taxonomy/role/StatementCONSOLIDATEDSTATEMENTSOFSHAREHOLDERSEQUITY">
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_AdjustmentsToAdditionalPaidInCapitalTaxEffectFromShareBasedCompensation" xlink:type="locator" xlink:label="us-gaap_AdjustmentsToAdditionalPaidInCapitalTaxEffectFromShareBasedCompensation" />
    <loc xlink:href="medp-20161231.xsd#medp_AdjustmentsToAdditionalPaidInCapitalTaxEffectOfInitialPublicOfferingRelatedCosts" xlink:type="locator" xlink:label="medp_AdjustmentsToAdditionalPaidInCapitalTaxEffectOfInitialPublicOfferingRelatedCosts" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_AdjustmentToAdditionalPaidInCapitalIncomeTaxEffectFromShareBasedCompensationNet" xlink:type="locator" xlink:label="us-gaap_AdjustmentToAdditionalPaidInCapitalIncomeTaxEffectFromShareBasedCompensationNet" />
    <loc xlink:href="medp-20161231.xsd#medp_AdjustmentsToAdditionalPaidInCapitalLiabilityReclassificationUponInitialPublicOfferingStockOptions" xlink:type="locator" xlink:label="medp_AdjustmentsToAdditionalPaidInCapitalLiabilityReclassificationUponInitialPublicOfferingStockOptions" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_AdjustmentsToAdditionalPaidInCapitalStockIssuedIssuanceCosts" xlink:type="locator" xlink:label="us-gaap_AdjustmentsToAdditionalPaidInCapitalStockIssuedIssuanceCosts" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_StockIssuedDuringPeriodValueStockOptionsExercised" xlink:type="locator" xlink:label="us-gaap_StockIssuedDuringPeriodValueStockOptionsExercised" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue" xlink:type="locator" xlink:label="us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_OtherComprehensiveIncomeLossForeignCurrencyTransactionAndTranslationAdjustmentNetOfTax" xlink:type="locator" xlink:label="us-gaap_OtherComprehensiveIncomeLossForeignCurrencyTransactionAndTranslationAdjustmentNetOfTax" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_StockIssuedDuringPeriodValueNewIssues" xlink:type="locator" xlink:label="us-gaap_StockIssuedDuringPeriodValueNewIssues" />
    <loc xlink:href="medp-20161231.xsd#medp_StockholdersEquityAtAcquisitionDate" xlink:type="locator" xlink:label="medp_StockholdersEquityAtAcquisitionDate" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_NetIncomeLoss" xlink:type="locator" xlink:label="us-gaap_NetIncomeLoss" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_StockholdersEquity" xlink:type="locator" xlink:label="us-gaap_StockholdersEquity" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_PredecessorMember" xlink:type="locator" xlink:label="us-gaap_PredecessorMember" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ScenarioUnspecifiedDomain" xlink:type="locator" xlink:label="us-gaap_ScenarioUnspecifiedDomain" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_StatementScenarioAxis" xlink:type="locator" xlink:label="us-gaap_StatementScenarioAxis" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeMember" xlink:type="locator" xlink:label="us-gaap_AccumulatedOtherComprehensiveIncomeMember" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_RetainedEarningsMember" xlink:type="locator" xlink:label="us-gaap_RetainedEarningsMember" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_AdditionalPaidInCapitalMember" xlink:type="locator" xlink:label="us-gaap_AdditionalPaidInCapitalMember" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_CommonStockMember" xlink:type="locator" xlink:label="us-gaap_CommonStockMember" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_EquityComponentDomain" xlink:type="locator" xlink:label="us-gaap_EquityComponentDomain_2" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_EquityComponentDomain" xlink:type="locator" xlink:label="us-gaap_EquityComponentDomain" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_StatementEquityComponentsAxis" xlink:type="locator" xlink:label="us-gaap_StatementEquityComponentsAxis" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_StatementTable" xlink:type="locator" xlink:label="us-gaap_StatementTable" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_StatementLineItems" xlink:type="locator" xlink:label="us-gaap_StatementLineItems" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="us-gaap_StatementLineItems" xlink:to="us-gaap_StatementTable" order="10010.00" priority="2" use="optional" xbrldt:contextElement="segment" xbrldt:closed="true" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="us-gaap_StatementTable" xlink:to="us-gaap_StatementEquityComponentsAxis" order="10040.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="us-gaap_StatementEquityComponentsAxis" xlink:to="us-gaap_EquityComponentDomain_2" order="10060.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_StatementEquityComponentsAxis" xlink:to="us-gaap_EquityComponentDomain" order="10060.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_EquityComponentDomain" xlink:to="us-gaap_CommonStockMember" order="10080.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_EquityComponentDomain" xlink:to="us-gaap_AdditionalPaidInCapitalMember" order="10100.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_EquityComponentDomain" xlink:to="us-gaap_RetainedEarningsMember" order="10120.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_EquityComponentDomain" xlink:to="us-gaap_AccumulatedOtherComprehensiveIncomeMember" order="10140.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="us-gaap_StatementTable" xlink:to="us-gaap_StatementScenarioAxis" order="10150.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_StatementScenarioAxis" xlink:to="us-gaap_ScenarioUnspecifiedDomain" order="10170.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ScenarioUnspecifiedDomain" xlink:to="us-gaap_PredecessorMember" order="10190.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_StatementLineItems" xlink:to="us-gaap_StockholdersEquity" order="10800.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_StatementLineItems" xlink:to="us-gaap_NetIncomeLoss" order="11020.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_StatementLineItems" xlink:to="medp_StockholdersEquityAtAcquisitionDate" order="11160.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_StatementLineItems" xlink:to="us-gaap_StockIssuedDuringPeriodValueNewIssues" order="11280.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_StatementLineItems" xlink:to="us-gaap_OtherComprehensiveIncomeLossForeignCurrencyTransactionAndTranslationAdjustmentNetOfTax" order="11400.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_StatementLineItems" xlink:to="us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue" order="11540.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_StatementLineItems" xlink:to="us-gaap_StockIssuedDuringPeriodValueStockOptionsExercised" order="11660.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_StatementLineItems" xlink:to="us-gaap_AdjustmentsToAdditionalPaidInCapitalStockIssuedIssuanceCosts" order="11960.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_StatementLineItems" xlink:to="medp_AdjustmentsToAdditionalPaidInCapitalLiabilityReclassificationUponInitialPublicOfferingStockOptions" order="12080.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_StatementLineItems" xlink:to="us-gaap_AdjustmentToAdditionalPaidInCapitalIncomeTaxEffectFromShareBasedCompensationNet" order="12200.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_StatementLineItems" xlink:to="medp_AdjustmentsToAdditionalPaidInCapitalTaxEffectOfInitialPublicOfferingRelatedCosts" order="12760.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_StatementLineItems" xlink:to="us-gaap_AdjustmentsToAdditionalPaidInCapitalTaxEffectFromShareBasedCompensation" order="12880.00" priority="2" use="optional" />
  </definitionLink>
  <roleRef roleURI="http://www.medpace.com/20161231/taxonomy/role/StatementCONSOLIDATEDSTATEMENTSOFCASHFLOWS" xlink:href="medp-20161231.xsd#Role_StatementCONSOLIDATEDSTATEMENTSOFCASHFLOWS" xlink:type="simple" />
  <definitionLink xlink:type="extended" xlink:role="http://www.medpace.com/20161231/taxonomy/role/StatementCONSOLIDATEDSTATEMENTSOFCASHFLOWS">
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_NoncashOrPartNoncashAcquisitionFixedAssetsAcquired1" xlink:type="locator" xlink:label="us-gaap_NoncashOrPartNoncashAcquisitionFixedAssetsAcquired1" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_InterestPaid" xlink:type="locator" xlink:label="us-gaap_InterestPaid" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_IncomeTaxesPaidNet" xlink:type="locator" xlink:label="us-gaap_IncomeTaxesPaidNet" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_SupplementalCashFlowInformationAbstract" xlink:type="locator" xlink:label="us-gaap_SupplementalCashFlowInformationAbstract" />
    <loc xlink:href="medp-20161231.xsd#medp_CashAndCashEquivalentsAndRestrictedCashAtCarryingValue" xlink:type="locator" xlink:label="medp_CashAndCashEquivalentsAndRestrictedCashAtCarryingValue" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_CashAndCashEquivalentsPeriodIncreaseDecreaseExcludingExchangeRateEffect" xlink:type="locator" xlink:label="us-gaap_CashAndCashEquivalentsPeriodIncreaseDecreaseExcludingExchangeRateEffect" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_EffectOfExchangeRateOnCashAndCashEquivalentsContinuingOperations" xlink:type="locator" xlink:label="us-gaap_EffectOfExchangeRateOnCashAndCashEquivalentsContinuingOperations" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_NetCashProvidedByUsedInFinancingActivitiesContinuingOperations" xlink:type="locator" xlink:label="us-gaap_NetCashProvidedByUsedInFinancingActivitiesContinuingOperations" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ProceedsFromIssuanceOfCommonStock" xlink:type="locator" xlink:label="us-gaap_ProceedsFromIssuanceOfCommonStock" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_PaymentsOfDebtExtinguishmentCosts" xlink:type="locator" xlink:label="us-gaap_PaymentsOfDebtExtinguishmentCosts" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_RepaymentsOfLongTermCapitalLeaseObligations" xlink:type="locator" xlink:label="us-gaap_RepaymentsOfLongTermCapitalLeaseObligations" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_PaymentsOfDebtIssuanceCosts" xlink:type="locator" xlink:label="us-gaap_PaymentsOfDebtIssuanceCosts" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_RepaymentsOfLinesOfCredit" xlink:type="locator" xlink:label="us-gaap_RepaymentsOfLinesOfCredit" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ProceedsFromLinesOfCredit" xlink:type="locator" xlink:label="us-gaap_ProceedsFromLinesOfCredit" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_RepaymentsOfDebt" xlink:type="locator" xlink:label="us-gaap_RepaymentsOfDebt" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ProceedsFromIssuanceOfDebt" xlink:type="locator" xlink:label="us-gaap_ProceedsFromIssuanceOfDebt" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ExcessTaxBenefitFromShareBasedCompensationFinancingActivities" xlink:type="locator" xlink:label="us-gaap_ExcessTaxBenefitFromShareBasedCompensationFinancingActivities" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ProceedsFromStockOptionsExercised" xlink:type="locator" xlink:label="us-gaap_ProceedsFromStockOptionsExercised" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_PaymentsOfStockIssuanceCosts" xlink:type="locator" xlink:label="us-gaap_PaymentsOfStockIssuanceCosts" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_NetCashProvidedByUsedInFinancingActivitiesContinuingOperationsAbstract" xlink:type="locator" xlink:label="us-gaap_NetCashProvidedByUsedInFinancingActivitiesContinuingOperationsAbstract" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_NetCashProvidedByUsedInInvestingActivitiesContinuingOperations" xlink:type="locator" xlink:label="us-gaap_NetCashProvidedByUsedInInvestingActivitiesContinuingOperations" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_PaymentsForProceedsFromOtherInvestingActivities" xlink:type="locator" xlink:label="us-gaap_PaymentsForProceedsFromOtherInvestingActivities" />
    <loc xlink:href="medp-20161231.xsd#medp_PaymentsToAcquireBusinessesNetOfCashAndRestrictedCashAcquired" xlink:type="locator" xlink:label="medp_PaymentsToAcquireBusinessesNetOfCashAndRestrictedCashAcquired" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_PaymentsToAcquirePropertyPlantAndEquipment" xlink:type="locator" xlink:label="us-gaap_PaymentsToAcquirePropertyPlantAndEquipment" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_NetCashProvidedByUsedInInvestingActivitiesContinuingOperationsAbstract" xlink:type="locator" xlink:label="us-gaap_NetCashProvidedByUsedInInvestingActivitiesContinuingOperationsAbstract" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_NetCashProvidedByUsedInOperatingActivitiesContinuingOperations" xlink:type="locator" xlink:label="us-gaap_NetCashProvidedByUsedInOperatingActivitiesContinuingOperations" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_IncreaseDecreaseInOtherOperatingCapitalNet" xlink:type="locator" xlink:label="us-gaap_IncreaseDecreaseInOtherOperatingCapitalNet" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_IncreaseDecreaseInDeferredRevenue" xlink:type="locator" xlink:label="us-gaap_IncreaseDecreaseInDeferredRevenue" />
    <loc xlink:href="medp-20161231.xsd#medp_IncreaseDecreaseInPreFundedStudyCosts" xlink:type="locator" xlink:label="medp_IncreaseDecreaseInPreFundedStudyCosts" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_IncreaseDecreaseInAccruedLiabilities" xlink:type="locator" xlink:label="us-gaap_IncreaseDecreaseInAccruedLiabilities" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_IncreaseDecreaseInAccountsPayable" xlink:type="locator" xlink:label="us-gaap_IncreaseDecreaseInAccountsPayable" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_IncreaseDecreaseInPrepaidDeferredExpenseAndOtherAssets" xlink:type="locator" xlink:label="us-gaap_IncreaseDecreaseInPrepaidDeferredExpenseAndOtherAssets" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_IncreaseDecreaseInReceivables" xlink:type="locator" xlink:label="us-gaap_IncreaseDecreaseInReceivables" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_IncreaseDecreaseInOtherOperatingAssetsAndLiabilitiesNetAbstract" xlink:type="locator" xlink:label="us-gaap_IncreaseDecreaseInOtherOperatingAssetsAndLiabilitiesNetAbstract" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_OtherNoncashIncomeExpense" xlink:type="locator" xlink:label="us-gaap_OtherNoncashIncomeExpense" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_GoodwillImpairmentLoss" xlink:type="locator" xlink:label="us-gaap_GoodwillImpairmentLoss" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_DeferredIncomeTaxExpenseBenefit" xlink:type="locator" xlink:label="us-gaap_DeferredIncomeTaxExpenseBenefit" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_GainsLossesOnExtinguishmentOfDebtBeforeWriteOffOfDeferredDebtIssuanceCost" xlink:type="locator" xlink:label="us-gaap_GainsLossesOnExtinguishmentOfDebtBeforeWriteOffOfDeferredDebtIssuanceCost" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_AmortizationOfFinancingCostsAndDiscounts" xlink:type="locator" xlink:label="us-gaap_AmortizationOfFinancingCostsAndDiscounts" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ShareBasedCompensation" xlink:type="locator" xlink:label="us-gaap_ShareBasedCompensation" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_AmortizationOfIntangibleAssets" xlink:type="locator" xlink:label="us-gaap_AmortizationOfIntangibleAssets" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_Depreciation" xlink:type="locator" xlink:label="us-gaap_Depreciation" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract" xlink:type="locator" xlink:label="us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_NetIncomeLoss" xlink:type="locator" xlink:label="us-gaap_NetIncomeLoss" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_NetCashProvidedByUsedInOperatingActivitiesContinuingOperationsAbstract" xlink:type="locator" xlink:label="us-gaap_NetCashProvidedByUsedInOperatingActivitiesContinuingOperationsAbstract" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_PredecessorMember" xlink:type="locator" xlink:label="us-gaap_PredecessorMember" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ScenarioUnspecifiedDomain" xlink:type="locator" xlink:label="us-gaap_ScenarioUnspecifiedDomain" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_StatementScenarioAxis" xlink:type="locator" xlink:label="us-gaap_StatementScenarioAxis" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_StatementTable" xlink:type="locator" xlink:label="us-gaap_StatementTable" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_StatementLineItems" xlink:type="locator" xlink:label="us-gaap_StatementLineItems" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="us-gaap_StatementLineItems" xlink:to="us-gaap_StatementTable" order="10350.00" priority="2" use="optional" xbrldt:contextElement="segment" xbrldt:closed="true" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="us-gaap_StatementTable" xlink:to="us-gaap_StatementScenarioAxis" order="10380.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_StatementScenarioAxis" xlink:to="us-gaap_ScenarioUnspecifiedDomain" order="10400.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ScenarioUnspecifiedDomain" xlink:to="us-gaap_PredecessorMember" order="10420.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_StatementLineItems" xlink:to="us-gaap_NetCashProvidedByUsedInOperatingActivitiesContinuingOperationsAbstract" order="10450.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_NetCashProvidedByUsedInOperatingActivitiesContinuingOperationsAbstract" xlink:to="us-gaap_NetIncomeLoss" order="10610.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_NetCashProvidedByUsedInOperatingActivitiesContinuingOperationsAbstract" xlink:to="us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract" order="10690.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract" xlink:to="us-gaap_Depreciation" order="10850.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract" xlink:to="us-gaap_AmortizationOfIntangibleAssets" order="10930.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract" xlink:to="us-gaap_ShareBasedCompensation" order="11010.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract" xlink:to="us-gaap_AmortizationOfFinancingCostsAndDiscounts" order="11170.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract" xlink:to="us-gaap_GainsLossesOnExtinguishmentOfDebtBeforeWriteOffOfDeferredDebtIssuanceCost" order="11330.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract" xlink:to="us-gaap_DeferredIncomeTaxExpenseBenefit" order="11490.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract" xlink:to="us-gaap_GoodwillImpairmentLoss" order="11650.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract" xlink:to="us-gaap_OtherNoncashIncomeExpense" order="11730.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract" xlink:to="us-gaap_IncreaseDecreaseInOtherOperatingAssetsAndLiabilitiesNetAbstract" order="11890.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_IncreaseDecreaseInOtherOperatingAssetsAndLiabilitiesNetAbstract" xlink:to="us-gaap_IncreaseDecreaseInReceivables" order="12050.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_IncreaseDecreaseInOtherOperatingAssetsAndLiabilitiesNetAbstract" xlink:to="us-gaap_IncreaseDecreaseInPrepaidDeferredExpenseAndOtherAssets" order="12210.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_IncreaseDecreaseInOtherOperatingAssetsAndLiabilitiesNetAbstract" xlink:to="us-gaap_IncreaseDecreaseInAccountsPayable" order="12370.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_IncreaseDecreaseInOtherOperatingAssetsAndLiabilitiesNetAbstract" xlink:to="us-gaap_IncreaseDecreaseInAccruedLiabilities" order="12530.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_IncreaseDecreaseInOtherOperatingAssetsAndLiabilitiesNetAbstract" xlink:to="medp_IncreaseDecreaseInPreFundedStudyCosts" order="12690.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_IncreaseDecreaseInOtherOperatingAssetsAndLiabilitiesNetAbstract" xlink:to="us-gaap_IncreaseDecreaseInDeferredRevenue" order="12850.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_IncreaseDecreaseInOtherOperatingAssetsAndLiabilitiesNetAbstract" xlink:to="us-gaap_IncreaseDecreaseInOtherOperatingCapitalNet" order="13010.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_NetCashProvidedByUsedInOperatingActivitiesContinuingOperationsAbstract" xlink:to="us-gaap_NetCashProvidedByUsedInOperatingActivitiesContinuingOperations" order="13170.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_StatementLineItems" xlink:to="us-gaap_NetCashProvidedByUsedInInvestingActivitiesContinuingOperationsAbstract" order="13330.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_NetCashProvidedByUsedInInvestingActivitiesContinuingOperationsAbstract" xlink:to="us-gaap_PaymentsToAcquirePropertyPlantAndEquipment" order="13490.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_NetCashProvidedByUsedInInvestingActivitiesContinuingOperationsAbstract" xlink:to="medp_PaymentsToAcquireBusinessesNetOfCashAndRestrictedCashAcquired" order="13650.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_NetCashProvidedByUsedInInvestingActivitiesContinuingOperationsAbstract" xlink:to="us-gaap_PaymentsForProceedsFromOtherInvestingActivities" order="13810.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_NetCashProvidedByUsedInInvestingActivitiesContinuingOperationsAbstract" xlink:to="us-gaap_NetCashProvidedByUsedInInvestingActivitiesContinuingOperations" order="13970.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_StatementLineItems" xlink:to="us-gaap_NetCashProvidedByUsedInFinancingActivitiesContinuingOperationsAbstract" order="14130.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_NetCashProvidedByUsedInFinancingActivitiesContinuingOperationsAbstract" xlink:to="us-gaap_PaymentsOfStockIssuanceCosts" order="14290.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_NetCashProvidedByUsedInFinancingActivitiesContinuingOperationsAbstract" xlink:to="us-gaap_ProceedsFromStockOptionsExercised" order="14450.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_NetCashProvidedByUsedInFinancingActivitiesContinuingOperationsAbstract" xlink:to="us-gaap_ExcessTaxBenefitFromShareBasedCompensationFinancingActivities" order="14610.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_NetCashProvidedByUsedInFinancingActivitiesContinuingOperationsAbstract" xlink:to="us-gaap_ProceedsFromIssuanceOfDebt" order="14770.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_NetCashProvidedByUsedInFinancingActivitiesContinuingOperationsAbstract" xlink:to="us-gaap_RepaymentsOfDebt" order="14930.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_NetCashProvidedByUsedInFinancingActivitiesContinuingOperationsAbstract" xlink:to="us-gaap_ProceedsFromLinesOfCredit" order="15090.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_NetCashProvidedByUsedInFinancingActivitiesContinuingOperationsAbstract" xlink:to="us-gaap_RepaymentsOfLinesOfCredit" order="15250.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_NetCashProvidedByUsedInFinancingActivitiesContinuingOperationsAbstract" xlink:to="us-gaap_PaymentsOfDebtIssuanceCosts" order="15410.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_NetCashProvidedByUsedInFinancingActivitiesContinuingOperationsAbstract" xlink:to="us-gaap_RepaymentsOfLongTermCapitalLeaseObligations" order="15570.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_NetCashProvidedByUsedInFinancingActivitiesContinuingOperationsAbstract" xlink:to="us-gaap_PaymentsOfDebtExtinguishmentCosts" order="15730.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_NetCashProvidedByUsedInFinancingActivitiesContinuingOperationsAbstract" xlink:to="us-gaap_ProceedsFromIssuanceOfCommonStock" order="15890.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_NetCashProvidedByUsedInFinancingActivitiesContinuingOperationsAbstract" xlink:to="us-gaap_NetCashProvidedByUsedInFinancingActivitiesContinuingOperations" order="16050.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_StatementLineItems" xlink:to="us-gaap_EffectOfExchangeRateOnCashAndCashEquivalentsContinuingOperations" order="16210.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_StatementLineItems" xlink:to="us-gaap_CashAndCashEquivalentsPeriodIncreaseDecreaseExcludingExchangeRateEffect" order="16370.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_StatementLineItems" xlink:to="medp_CashAndCashEquivalentsAndRestrictedCashAtCarryingValue" order="16530.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_StatementLineItems" xlink:to="us-gaap_SupplementalCashFlowInformationAbstract" order="16810.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_SupplementalCashFlowInformationAbstract" xlink:to="us-gaap_IncomeTaxesPaidNet" order="16970.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_SupplementalCashFlowInformationAbstract" xlink:to="us-gaap_InterestPaid" order="17130.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_SupplementalCashFlowInformationAbstract" xlink:to="us-gaap_NoncashOrPartNoncashAcquisitionFixedAssetsAcquired1" order="17290.00" priority="2" use="optional" />
  </definitionLink>
  <roleRef roleURI="http://www.medpace.com/20161231/taxonomy/role/DisclosureBasisOfPresentationAdditionalInformationDetails" xlink:href="medp-20161231.xsd#Role_DisclosureBasisOfPresentationAdditionalInformationDetails" xlink:type="simple" />
  <definitionLink xlink:type="extended" xlink:role="http://www.medpace.com/20161231/taxonomy/role/DisclosureBasisOfPresentationAdditionalInformationDetails">
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_PaymentsOfStockIssuanceCosts" xlink:type="locator" xlink:label="us-gaap_PaymentsOfStockIssuanceCosts" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_RepaymentsOfLinesOfCredit" xlink:type="locator" xlink:label="us-gaap_RepaymentsOfLinesOfCredit" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ProceedsFromIssuanceInitialPublicOffering" xlink:type="locator" xlink:label="us-gaap_ProceedsFromIssuanceInitialPublicOffering" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_SaleOfStockNumberOfSharesIssuedInTransaction" xlink:type="locator" xlink:label="us-gaap_SaleOfStockNumberOfSharesIssuedInTransaction" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_SaleOfStockPricePerShare" xlink:type="locator" xlink:label="us-gaap_SaleOfStockPricePerShare" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_StockholdersEquityNoteStockSplitConversionRatio1" xlink:type="locator" xlink:label="us-gaap_StockholdersEquityNoteStockSplitConversionRatio1" />
    <loc xlink:href="medp-20161231.xsd#medp_TwoThousandFourteenSeniorSecuredTermLoanFacilityMember" xlink:type="locator" xlink:label="medp_TwoThousandFourteenSeniorSecuredTermLoanFacilityMember" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_LongtermDebtTypeDomain" xlink:type="locator" xlink:label="us-gaap_LongtermDebtTypeDomain_2" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_LongtermDebtTypeDomain" xlink:type="locator" xlink:label="us-gaap_LongtermDebtTypeDomain" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_LongtermDebtTypeAxis" xlink:type="locator" xlink:label="us-gaap_LongtermDebtTypeAxis" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_OverAllotmentOptionMember" xlink:type="locator" xlink:label="us-gaap_OverAllotmentOptionMember" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_IPOMember" xlink:type="locator" xlink:label="us-gaap_IPOMember" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_SaleOfStockNameOfTransactionDomain" xlink:type="locator" xlink:label="us-gaap_SaleOfStockNameOfTransactionDomain_2" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_SaleOfStockNameOfTransactionDomain" xlink:type="locator" xlink:label="us-gaap_SaleOfStockNameOfTransactionDomain" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_SubsidiarySaleOfStockAxis" xlink:type="locator" xlink:label="us-gaap_SubsidiarySaleOfStockAxis" />
    <loc xlink:href="medp-20161231.xsd#medp_BasisOfPresentationTable" xlink:type="locator" xlink:label="medp_BasisOfPresentationTable" />
    <loc xlink:href="medp-20161231.xsd#medp_BasisOfPresentationLineItems" xlink:type="locator" xlink:label="medp_BasisOfPresentationLineItems" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="medp_BasisOfPresentationLineItems" xlink:to="medp_BasisOfPresentationTable" order="10010.00" priority="2" use="optional" xbrldt:contextElement="segment" xbrldt:closed="true" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="medp_BasisOfPresentationTable" xlink:to="us-gaap_SubsidiarySaleOfStockAxis" order="10040.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="us-gaap_SubsidiarySaleOfStockAxis" xlink:to="us-gaap_SaleOfStockNameOfTransactionDomain_2" order="10060.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_SubsidiarySaleOfStockAxis" xlink:to="us-gaap_SaleOfStockNameOfTransactionDomain" order="10060.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_SaleOfStockNameOfTransactionDomain" xlink:to="us-gaap_IPOMember" order="10080.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_SaleOfStockNameOfTransactionDomain" xlink:to="us-gaap_OverAllotmentOptionMember" order="10160.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="medp_BasisOfPresentationTable" xlink:to="us-gaap_LongtermDebtTypeAxis" order="10170.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="us-gaap_LongtermDebtTypeAxis" xlink:to="us-gaap_LongtermDebtTypeDomain_2" order="10190.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_LongtermDebtTypeAxis" xlink:to="us-gaap_LongtermDebtTypeDomain" order="10190.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_LongtermDebtTypeDomain" xlink:to="medp_TwoThousandFourteenSeniorSecuredTermLoanFacilityMember" order="10210.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="medp_BasisOfPresentationLineItems" xlink:to="us-gaap_StockholdersEquityNoteStockSplitConversionRatio1" order="10240.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="medp_BasisOfPresentationLineItems" xlink:to="us-gaap_SaleOfStockPricePerShare" order="10310.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="medp_BasisOfPresentationLineItems" xlink:to="us-gaap_SaleOfStockNumberOfSharesIssuedInTransaction" order="10350.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="medp_BasisOfPresentationLineItems" xlink:to="us-gaap_ProceedsFromIssuanceInitialPublicOffering" order="10390.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="medp_BasisOfPresentationLineItems" xlink:to="us-gaap_RepaymentsOfLinesOfCredit" order="10430.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="medp_BasisOfPresentationLineItems" xlink:to="us-gaap_PaymentsOfStockIssuanceCosts" order="10470.00" priority="2" use="optional" />
  </definitionLink>
  <roleRef roleURI="http://www.medpace.com/20161231/taxonomy/role/DisclosureChangeInControlAdditionalInformationDetails" xlink:href="medp-20161231.xsd#Role_DisclosureChangeInControlAdditionalInformationDetails" xlink:type="simple" />
  <definitionLink xlink:type="extended" xlink:role="http://www.medpace.com/20161231/taxonomy/role/DisclosureChangeInControlAdditionalInformationDetails">
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_OtherLiabilitiesNoncurrent" xlink:type="locator" xlink:label="us-gaap_OtherLiabilitiesNoncurrent" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_OtherLiabilitiesCurrent" xlink:type="locator" xlink:label="us-gaap_OtherLiabilitiesCurrent" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_OtherAssetsNoncurrent" xlink:type="locator" xlink:label="us-gaap_OtherAssetsNoncurrent" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_PrepaidExpenseAndOtherAssetsCurrent" xlink:type="locator" xlink:label="us-gaap_PrepaidExpenseAndOtherAssetsCurrent" />
    <loc xlink:href="medp-20161231.xsd#medp_GainOnFinalSettlementOfIndemnifications" xlink:type="locator" xlink:label="medp_GainOnFinalSettlementOfIndemnifications" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_MinorityInterestOwnershipPercentageByNoncontrollingOwners" xlink:type="locator" xlink:label="us-gaap_MinorityInterestOwnershipPercentageByNoncontrollingOwners" />
    <loc xlink:href="medp-20161231.xsd#medp_BusinessCombinationContingentConsiderationExcessCashGenerated" xlink:type="locator" xlink:label="medp_BusinessCombinationContingentConsiderationExcessCashGenerated" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_MinorityInterestOwnershipPercentageByParent" xlink:type="locator" xlink:label="us-gaap_MinorityInterestOwnershipPercentageByParent" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_InvestmentAdvisoryFees" xlink:type="locator" xlink:label="us-gaap_InvestmentAdvisoryFees" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_BusinessCombinationIntegrationRelatedCosts" xlink:type="locator" xlink:label="us-gaap_BusinessCombinationIntegrationRelatedCosts" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_BusinessCombinationConsiderationTransferred1" xlink:type="locator" xlink:label="us-gaap_BusinessCombinationConsiderationTransferred1" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_BusinessAcquisitionPercentageOfVotingInterestsAcquired" xlink:type="locator" xlink:label="us-gaap_BusinessAcquisitionPercentageOfVotingInterestsAcquired" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_MaximumMember" xlink:type="locator" xlink:label="us-gaap_MaximumMember" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_RangeMember" xlink:type="locator" xlink:label="us-gaap_RangeMember_2" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_RangeMember" xlink:type="locator" xlink:label="us-gaap_RangeMember" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_RangeAxis" xlink:type="locator" xlink:label="us-gaap_RangeAxis" />
    <loc xlink:href="medp-20161231.xsd#medp_MergerAgreementMember" xlink:type="locator" xlink:label="medp_MergerAgreementMember" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_BusinessAcquisitionAcquireeDomain" xlink:type="locator" xlink:label="us-gaap_BusinessAcquisitionAcquireeDomain_2" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_BusinessAcquisitionAcquireeDomain" xlink:type="locator" xlink:label="us-gaap_BusinessAcquisitionAcquireeDomain" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_BusinessAcquisitionAxis" xlink:type="locator" xlink:label="us-gaap_BusinessAcquisitionAxis" />
    <loc xlink:href="medp-20161231.xsd#medp_MedpaceInvestorsLLCMember" xlink:type="locator" xlink:label="medp_MedpaceInvestorsLLCMember" />
    <loc xlink:href="medp-20161231.xsd#medp_PostAcquisitionMember" xlink:type="locator" xlink:label="medp_PostAcquisitionMember" />
    <loc xlink:href="medp-20161231.xsd#medp_CinvenCapitalManagementVGeneralPartnerLimitedMember" xlink:type="locator" xlink:label="medp_CinvenCapitalManagementVGeneralPartnerLimitedMember" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_RelatedPartyDomain" xlink:type="locator" xlink:label="us-gaap_RelatedPartyDomain_2" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_RelatedPartyDomain" xlink:type="locator" xlink:label="us-gaap_RelatedPartyDomain" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_RelatedPartyTransactionsByRelatedPartyAxis" xlink:type="locator" xlink:label="us-gaap_RelatedPartyTransactionsByRelatedPartyAxis" />
    <loc xlink:href="medp-20161231.xsd#medp_PriorAcquisitionMember" xlink:type="locator" xlink:label="medp_PriorAcquisitionMember" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_PredecessorMember" xlink:type="locator" xlink:label="us-gaap_PredecessorMember" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ScenarioUnspecifiedDomain" xlink:type="locator" xlink:label="us-gaap_ScenarioUnspecifiedDomain" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_StatementScenarioAxis" xlink:type="locator" xlink:label="us-gaap_StatementScenarioAxis" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable" xlink:type="locator" xlink:label="us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_BusinessAcquisitionLineItems" xlink:type="locator" xlink:label="us-gaap_BusinessAcquisitionLineItems" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="us-gaap_BusinessAcquisitionLineItems" xlink:to="us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable" order="10010.00" priority="2" use="optional" xbrldt:contextElement="segment" xbrldt:closed="true" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable" xlink:to="us-gaap_StatementScenarioAxis" order="10040.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_StatementScenarioAxis" xlink:to="us-gaap_ScenarioUnspecifiedDomain" order="10060.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ScenarioUnspecifiedDomain" xlink:to="us-gaap_PredecessorMember" order="10080.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ScenarioUnspecifiedDomain" xlink:to="medp_PriorAcquisitionMember" order="10150.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable" xlink:to="us-gaap_RelatedPartyTransactionsByRelatedPartyAxis" order="10160.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="us-gaap_RelatedPartyTransactionsByRelatedPartyAxis" xlink:to="us-gaap_RelatedPartyDomain_2" order="10180.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_RelatedPartyTransactionsByRelatedPartyAxis" xlink:to="us-gaap_RelatedPartyDomain" order="10180.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_RelatedPartyDomain" xlink:to="medp_CinvenCapitalManagementVGeneralPartnerLimitedMember" order="10200.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ScenarioUnspecifiedDomain" xlink:to="medp_PostAcquisitionMember" order="10250.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_RelatedPartyDomain" xlink:to="medp_MedpaceInvestorsLLCMember" order="10340.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable" xlink:to="us-gaap_BusinessAcquisitionAxis" order="10350.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="us-gaap_BusinessAcquisitionAxis" xlink:to="us-gaap_BusinessAcquisitionAcquireeDomain_2" order="10370.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_BusinessAcquisitionAxis" xlink:to="us-gaap_BusinessAcquisitionAcquireeDomain" order="10370.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_BusinessAcquisitionAcquireeDomain" xlink:to="medp_MergerAgreementMember" order="10390.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable" xlink:to="us-gaap_RangeAxis" order="10500.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="us-gaap_RangeAxis" xlink:to="us-gaap_RangeMember_2" order="10520.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_RangeAxis" xlink:to="us-gaap_RangeMember" order="10520.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_RangeMember" xlink:to="us-gaap_MaximumMember" order="10540.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_BusinessAcquisitionLineItems" xlink:to="us-gaap_BusinessAcquisitionPercentageOfVotingInterestsAcquired" order="10570.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_BusinessAcquisitionLineItems" xlink:to="us-gaap_BusinessCombinationConsiderationTransferred1" order="10650.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_BusinessAcquisitionLineItems" xlink:to="us-gaap_BusinessCombinationIntegrationRelatedCosts" order="10730.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_BusinessAcquisitionLineItems" xlink:to="us-gaap_InvestmentAdvisoryFees" order="10790.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_BusinessAcquisitionLineItems" xlink:to="us-gaap_MinorityInterestOwnershipPercentageByParent" order="11040.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_BusinessAcquisitionLineItems" xlink:to="medp_BusinessCombinationContingentConsiderationExcessCashGenerated" order="11110.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_BusinessAcquisitionLineItems" xlink:to="us-gaap_MinorityInterestOwnershipPercentageByNoncontrollingOwners" order="11220.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_BusinessAcquisitionLineItems" xlink:to="medp_GainOnFinalSettlementOfIndemnifications" order="11340.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_BusinessAcquisitionLineItems" xlink:to="us-gaap_PrepaidExpenseAndOtherAssetsCurrent" order="11400.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_BusinessAcquisitionLineItems" xlink:to="us-gaap_OtherAssetsNoncurrent" order="11480.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_BusinessAcquisitionLineItems" xlink:to="us-gaap_OtherLiabilitiesCurrent" order="11560.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_BusinessAcquisitionLineItems" xlink:to="us-gaap_OtherLiabilitiesNoncurrent" order="11680.00" priority="2" use="optional" />
  </definitionLink>
  <roleRef roleURI="http://www.medpace.com/20161231/taxonomy/role/DisclosureChangeInControlScheduleOfSourcesAndUsesOfPurchasePriceConsiderationDetails" xlink:href="medp-20161231.xsd#Role_DisclosureChangeInControlScheduleOfSourcesAndUsesOfPurchasePriceConsiderationDetails" xlink:type="simple" />
  <definitionLink xlink:type="extended" xlink:role="http://www.medpace.com/20161231/taxonomy/role/DisclosureChangeInControlScheduleOfSourcesAndUsesOfPurchasePriceConsiderationDetails">
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_BusinessCombinationConsiderationTransferred1" xlink:type="locator" xlink:label="us-gaap_BusinessCombinationConsiderationTransferred1" />
    <loc xlink:href="medp-20161231.xsd#medp_BusinessCombinationSellingExpenses" xlink:type="locator" xlink:label="medp_BusinessCombinationSellingExpenses" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_RepaymentsOfAssumedDebt" xlink:type="locator" xlink:label="us-gaap_RepaymentsOfAssumedDebt" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ProceedsFromStockOptionsExercised" xlink:type="locator" xlink:label="us-gaap_ProceedsFromStockOptionsExercised" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_PaymentsForRepurchaseOfCommonStock" xlink:type="locator" xlink:label="us-gaap_PaymentsForRepurchaseOfCommonStock" />
    <loc xlink:href="medp-20161231.xsd#medp_BusinessCombinationUsesOfCashConsiderationAbstract" xlink:type="locator" xlink:label="medp_BusinessCombinationUsesOfCashConsiderationAbstract" />
    <loc xlink:href="medp-20161231.xsd#medp_ProceedsFromIssuanceOfDebtAndEquity" xlink:type="locator" xlink:label="medp_ProceedsFromIssuanceOfDebtAndEquity" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ProceedsFromDebtNetOfIssuanceCosts" xlink:type="locator" xlink:label="us-gaap_ProceedsFromDebtNetOfIssuanceCosts" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_LoanProcessingFee" xlink:type="locator" xlink:label="us-gaap_LoanProcessingFee" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_AmortizationOfFinancingCostsAndDiscounts" xlink:type="locator" xlink:label="us-gaap_AmortizationOfFinancingCostsAndDiscounts" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ProceedsFromLinesOfCredit" xlink:type="locator" xlink:label="us-gaap_ProceedsFromLinesOfCredit" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ProceedsFromIssuanceOfLongTermDebt" xlink:type="locator" xlink:label="us-gaap_ProceedsFromIssuanceOfLongTermDebt" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ProceedsFromIssuanceOfCommonStock" xlink:type="locator" xlink:label="us-gaap_ProceedsFromIssuanceOfCommonStock" />
    <loc xlink:href="medp-20161231.xsd#medp_BusinessCombinationSourcesOfCashConsiderationAbstract" xlink:type="locator" xlink:label="medp_BusinessCombinationSourcesOfCashConsiderationAbstract" />
    <loc xlink:href="medp-20161231.xsd#medp_MergerAgreementMember" xlink:type="locator" xlink:label="medp_MergerAgreementMember" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_BusinessAcquisitionAcquireeDomain" xlink:type="locator" xlink:label="us-gaap_BusinessAcquisitionAcquireeDomain" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_BusinessAcquisitionAxis" xlink:type="locator" xlink:label="us-gaap_BusinessAcquisitionAxis" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable" xlink:type="locator" xlink:label="us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_BusinessAcquisitionLineItems" xlink:type="locator" xlink:label="us-gaap_BusinessAcquisitionLineItems" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="us-gaap_BusinessAcquisitionLineItems" xlink:to="us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable" order="10110.00" priority="2" use="optional" xbrldt:contextElement="segment" xbrldt:closed="true" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable" xlink:to="us-gaap_BusinessAcquisitionAxis" order="10140.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_BusinessAcquisitionAxis" xlink:to="us-gaap_BusinessAcquisitionAcquireeDomain" order="10160.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_BusinessAcquisitionAcquireeDomain" xlink:to="medp_MergerAgreementMember" order="10180.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_BusinessAcquisitionLineItems" xlink:to="medp_BusinessCombinationSourcesOfCashConsiderationAbstract" order="10470.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="medp_BusinessCombinationSourcesOfCashConsiderationAbstract" xlink:to="us-gaap_ProceedsFromIssuanceOfCommonStock" order="10510.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="medp_BusinessCombinationSourcesOfCashConsiderationAbstract" xlink:to="us-gaap_ProceedsFromIssuanceOfLongTermDebt" order="10550.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="medp_BusinessCombinationSourcesOfCashConsiderationAbstract" xlink:to="us-gaap_ProceedsFromLinesOfCredit" order="10590.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="medp_BusinessCombinationSourcesOfCashConsiderationAbstract" xlink:to="us-gaap_AmortizationOfFinancingCostsAndDiscounts" order="10630.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="medp_BusinessCombinationSourcesOfCashConsiderationAbstract" xlink:to="us-gaap_LoanProcessingFee" order="10670.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="medp_BusinessCombinationSourcesOfCashConsiderationAbstract" xlink:to="us-gaap_ProceedsFromDebtNetOfIssuanceCosts" order="10710.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="medp_BusinessCombinationSourcesOfCashConsiderationAbstract" xlink:to="medp_ProceedsFromIssuanceOfDebtAndEquity" order="10750.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_BusinessAcquisitionLineItems" xlink:to="medp_BusinessCombinationUsesOfCashConsiderationAbstract" order="10790.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="medp_BusinessCombinationUsesOfCashConsiderationAbstract" xlink:to="us-gaap_PaymentsForRepurchaseOfCommonStock" order="10830.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="medp_BusinessCombinationUsesOfCashConsiderationAbstract" xlink:to="us-gaap_ProceedsFromStockOptionsExercised" order="10870.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="medp_BusinessCombinationUsesOfCashConsiderationAbstract" xlink:to="us-gaap_RepaymentsOfAssumedDebt" order="10910.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="medp_BusinessCombinationUsesOfCashConsiderationAbstract" xlink:to="medp_BusinessCombinationSellingExpenses" order="10950.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="medp_BusinessCombinationUsesOfCashConsiderationAbstract" xlink:to="us-gaap_BusinessCombinationConsiderationTransferred1" order="10990.00" priority="2" use="optional" />
  </definitionLink>
  <roleRef roleURI="http://www.medpace.com/20161231/taxonomy/role/DisclosureChangeInControlScheduleOfFairValueOfAssetsAcquiredAndLiabilitiesAssumedDetails" xlink:href="medp-20161231.xsd#Role_DisclosureChangeInControlScheduleOfFairValueOfAssetsAcquiredAndLiabilitiesAssumedDetails" xlink:type="simple" />
  <definitionLink xlink:type="extended" xlink:role="http://www.medpace.com/20161231/taxonomy/role/DisclosureChangeInControlScheduleOfFairValueOfAssetsAcquiredAndLiabilitiesAssumedDetails">
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredGoodwillAndLiabilitiesAssumedNet" xlink:type="locator" xlink:label="us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredGoodwillAndLiabilitiesAssumedNet" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedLiabilities" xlink:type="locator" xlink:label="us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedLiabilities" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNoncurrentLiabilitiesOther" xlink:type="locator" xlink:label="us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNoncurrentLiabilitiesOther" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedDeferredTaxLiabilities" xlink:type="locator" xlink:label="us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedDeferredTaxLiabilities" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNoncurrentLiabilitiesLongTermDebt" xlink:type="locator" xlink:label="us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNoncurrentLiabilitiesLongTermDebt" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCapitalLeaseObligation" xlink:type="locator" xlink:label="us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCapitalLeaseObligation" />
    <loc xlink:href="medp-20161231.xsd#medp_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedAdvancedBillings" xlink:type="locator" xlink:label="medp_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedAdvancedBillings" />
    <loc xlink:href="medp-20161231.xsd#medp_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedLiabilitiesPrefundedStudyCosts" xlink:type="locator" xlink:label="medp_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedLiabilitiesPrefundedStudyCosts" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentLiabilitiesAccountsPayable" xlink:type="locator" xlink:label="us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentLiabilitiesAccountsPayable" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedLiabilitiesAbstract" xlink:type="locator" xlink:label="us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedLiabilitiesAbstract" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedAssets" xlink:type="locator" xlink:label="us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedAssets" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedOtherNoncurrentAssets" xlink:type="locator" xlink:label="us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedOtherNoncurrentAssets" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedDeferredTaxAssets" xlink:type="locator" xlink:label="us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedDeferredTaxAssets" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedIntangibleAssetsOtherThanGoodwill" xlink:type="locator" xlink:label="us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedIntangibleAssetsOtherThanGoodwill" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_Goodwill" xlink:type="locator" xlink:label="us-gaap_Goodwill" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedPropertyPlantAndEquipment" xlink:type="locator" xlink:label="us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedPropertyPlantAndEquipment" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentAssetsPrepaidExpenseAndOtherAssets" xlink:type="locator" xlink:label="us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentAssetsPrepaidExpenseAndOtherAssets" />
    <loc xlink:href="medp-20161231.xsd#medp_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedReimbursablePassThroughExpenses" xlink:type="locator" xlink:label="medp_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedReimbursablePassThroughExpenses" />
    <loc xlink:href="medp-20161231.xsd#medp_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedUnbilledServices" xlink:type="locator" xlink:label="medp_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedUnbilledServices" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentAssetsReceivables" xlink:type="locator" xlink:label="us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentAssetsReceivables" />
    <loc xlink:href="medp-20161231.xsd#medp_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedRestrictedCash" xlink:type="locator" xlink:label="medp_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedRestrictedCash" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCashAndEquivalents" xlink:type="locator" xlink:label="us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCashAndEquivalents" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedAssetsAbstract" xlink:type="locator" xlink:label="us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedAssetsAbstract" />
    <loc xlink:href="medp-20161231.xsd#medp_MergerAgreementMember" xlink:type="locator" xlink:label="medp_MergerAgreementMember" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_BusinessAcquisitionAcquireeDomain" xlink:type="locator" xlink:label="us-gaap_BusinessAcquisitionAcquireeDomain" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_BusinessAcquisitionAxis" xlink:type="locator" xlink:label="us-gaap_BusinessAcquisitionAxis" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable" xlink:type="locator" xlink:label="us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_BusinessAcquisitionLineItems" xlink:type="locator" xlink:label="us-gaap_BusinessAcquisitionLineItems" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="us-gaap_BusinessAcquisitionLineItems" xlink:to="us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable" order="10210.00" priority="2" use="optional" xbrldt:contextElement="segment" xbrldt:closed="true" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable" xlink:to="us-gaap_BusinessAcquisitionAxis" order="10240.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_BusinessAcquisitionAxis" xlink:to="us-gaap_BusinessAcquisitionAcquireeDomain" order="10260.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_BusinessAcquisitionAcquireeDomain" xlink:to="medp_MergerAgreementMember" order="10280.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_BusinessAcquisitionLineItems" xlink:to="us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedAssetsAbstract" order="10750.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedAssetsAbstract" xlink:to="us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCashAndEquivalents" order="10790.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedAssetsAbstract" xlink:to="medp_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedRestrictedCash" order="10830.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedAssetsAbstract" xlink:to="us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentAssetsReceivables" order="10870.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedAssetsAbstract" xlink:to="medp_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedUnbilledServices" order="10910.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedAssetsAbstract" xlink:to="medp_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedReimbursablePassThroughExpenses" order="10950.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedAssetsAbstract" xlink:to="us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentAssetsPrepaidExpenseAndOtherAssets" order="10990.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedAssetsAbstract" xlink:to="us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedPropertyPlantAndEquipment" order="11030.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedAssetsAbstract" xlink:to="us-gaap_Goodwill" order="11070.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedAssetsAbstract" xlink:to="us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedIntangibleAssetsOtherThanGoodwill" order="11110.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedAssetsAbstract" xlink:to="us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedDeferredTaxAssets" order="11150.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedAssetsAbstract" xlink:to="us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedOtherNoncurrentAssets" order="11190.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedAssetsAbstract" xlink:to="us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedAssets" order="11230.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_BusinessAcquisitionLineItems" xlink:to="us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedLiabilitiesAbstract" order="11270.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedLiabilitiesAbstract" xlink:to="us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentLiabilitiesAccountsPayable" order="11310.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedLiabilitiesAbstract" xlink:to="medp_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedLiabilitiesPrefundedStudyCosts" order="11350.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedLiabilitiesAbstract" xlink:to="medp_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedAdvancedBillings" order="11390.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedLiabilitiesAbstract" xlink:to="us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCapitalLeaseObligation" order="11430.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedLiabilitiesAbstract" xlink:to="us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNoncurrentLiabilitiesLongTermDebt" order="11470.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedLiabilitiesAbstract" xlink:to="us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedDeferredTaxLiabilities" order="11510.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedLiabilitiesAbstract" xlink:to="us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNoncurrentLiabilitiesOther" order="11550.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedLiabilitiesAbstract" xlink:to="us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedLiabilities" order="11590.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedLiabilitiesAbstract" xlink:to="us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredGoodwillAndLiabilitiesAssumedNet" order="11630.00" priority="2" use="optional" />
  </definitionLink>
  <roleRef roleURI="http://www.medpace.com/20161231/taxonomy/role/DisclosureSummaryOfSignificantAccountingPoliciesAdditionalInformationDetails" xlink:href="medp-20161231.xsd#Role_DisclosureSummaryOfSignificantAccountingPoliciesAdditionalInformationDetails" xlink:type="simple" />
  <definitionLink xlink:type="extended" xlink:role="http://www.medpace.com/20161231/taxonomy/role/DisclosureSummaryOfSignificantAccountingPoliciesAdditionalInformationDetails">
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetUsefulLife" xlink:type="locator" xlink:label="us-gaap_FiniteLivedIntangibleAssetUsefulLife" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_PropertyPlantAndEquipmentUsefulLife" xlink:type="locator" xlink:label="us-gaap_PropertyPlantAndEquipmentUsefulLife" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_OtherAssetsNoncurrent" xlink:type="locator" xlink:label="us-gaap_OtherAssetsNoncurrent" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_PrepaidExpenseAndOtherAssetsCurrent" xlink:type="locator" xlink:label="us-gaap_PrepaidExpenseAndOtherAssetsCurrent" />
    <loc xlink:href="medp-20161231.xsd#medp_FairValueAssetsTransfersBetweenLevel1Level2AndLevel3" xlink:type="locator" xlink:label="medp_FairValueAssetsTransfersBetweenLevel1Level2AndLevel3" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount" xlink:type="locator" xlink:label="us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_UndistributedEarningsOfForeignSubsidiaries" xlink:type="locator" xlink:label="us-gaap_UndistributedEarningsOfForeignSubsidiaries" />
    <loc xlink:href="medp-20161231.xsd#medp_PaymentForPreFundedStudyCostDisbursements" xlink:type="locator" xlink:label="medp_PaymentForPreFundedStudyCostDisbursements" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_AdvertisingExpense" xlink:type="locator" xlink:label="us-gaap_AdvertisingExpense" />
    <loc xlink:href="medp-20161231.xsd#medp_NumberOfCustomersAccountedForMoreThanTenPercentOfAccountsReceivable" xlink:type="locator" xlink:label="medp_NumberOfCustomersAccountedForMoreThanTenPercentOfAccountsReceivable" />
    <loc xlink:href="medp-20161231.xsd#medp_SalesRebatesOnServiceRevenues" xlink:type="locator" xlink:label="medp_SalesRebatesOnServiceRevenues" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ForeignCurrencyTransactionGainLossBeforeTax" xlink:type="locator" xlink:label="us-gaap_ForeignCurrencyTransactionGainLossBeforeTax" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_MinimumMember" xlink:type="locator" xlink:label="us-gaap_MinimumMember" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_SoftwareAndSoftwareDevelopmentCostsMember" xlink:type="locator" xlink:label="us-gaap_SoftwareAndSoftwareDevelopmentCostsMember" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_BuildingMember" xlink:type="locator" xlink:label="us-gaap_BuildingMember" />
    <loc xlink:href="medp-20161231.xsd#medp_FurnitureAndFixturesAndOtherEquipmentMember" xlink:type="locator" xlink:label="medp_FurnitureAndFixturesAndOtherEquipmentMember" />
    <loc xlink:href="medp-20161231.xsd#medp_ComputerHardwareSoftwarePhoneAndMedicalImagingEquipmentMember" xlink:type="locator" xlink:label="medp_ComputerHardwareSoftwarePhoneAndMedicalImagingEquipmentMember" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_PropertyPlantAndEquipmentTypeDomain" xlink:type="locator" xlink:label="us-gaap_PropertyPlantAndEquipmentTypeDomain_2" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_PropertyPlantAndEquipmentTypeDomain" xlink:type="locator" xlink:label="us-gaap_PropertyPlantAndEquipmentTypeDomain" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_PropertyPlantAndEquipmentByTypeAxis" xlink:type="locator" xlink:label="us-gaap_PropertyPlantAndEquipmentByTypeAxis" />
    <loc xlink:href="medp-20161231.xsd#medp_PropertyInLeuvenBelgiumMember" xlink:type="locator" xlink:label="medp_PropertyInLeuvenBelgiumMember" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_MortgageLoansOnRealEstateNamePropertyTypeDomain" xlink:type="locator" xlink:label="us-gaap_MortgageLoansOnRealEstateNamePropertyTypeDomain_2" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_MortgageLoansOnRealEstateNamePropertyTypeDomain" xlink:type="locator" xlink:label="us-gaap_MortgageLoansOnRealEstateNamePropertyTypeDomain" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_MortgageLoansOnRealEstateDescriptionTypeOfPropertyAxis" xlink:type="locator" xlink:label="us-gaap_MortgageLoansOnRealEstateDescriptionTypeOfPropertyAxis" />
    <loc xlink:href="medp-20161231.xsd#medp_RSAsAndRSUsMember" xlink:type="locator" xlink:label="medp_RSAsAndRSUsMember" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_EmployeeStockOptionMember" xlink:type="locator" xlink:label="us-gaap_EmployeeStockOptionMember" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_AntidilutiveSecuritiesNameDomain" xlink:type="locator" xlink:label="us-gaap_AntidilutiveSecuritiesNameDomain_2" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_AntidilutiveSecuritiesNameDomain" xlink:type="locator" xlink:label="us-gaap_AntidilutiveSecuritiesNameDomain" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis" xlink:type="locator" xlink:label="us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_SellingGeneralAndAdministrativeExpensesMember" xlink:type="locator" xlink:label="us-gaap_SellingGeneralAndAdministrativeExpensesMember" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_MaximumMember" xlink:type="locator" xlink:label="us-gaap_MaximumMember" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_RangeMember" xlink:type="locator" xlink:label="us-gaap_RangeMember" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_RangeAxis" xlink:type="locator" xlink:label="us-gaap_RangeAxis" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_OtherNonoperatingIncomeExpenseMember" xlink:type="locator" xlink:label="us-gaap_OtherNonoperatingIncomeExpenseMember" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_IncomeStatementLocationDomain" xlink:type="locator" xlink:label="us-gaap_IncomeStatementLocationDomain_2" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_IncomeStatementLocationDomain" xlink:type="locator" xlink:label="us-gaap_IncomeStatementLocationDomain" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_IncomeStatementLocationAxis" xlink:type="locator" xlink:label="us-gaap_IncomeStatementLocationAxis" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_PredecessorMember" xlink:type="locator" xlink:label="us-gaap_PredecessorMember" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ScenarioUnspecifiedDomain" xlink:type="locator" xlink:label="us-gaap_ScenarioUnspecifiedDomain" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_StatementScenarioAxis" xlink:type="locator" xlink:label="us-gaap_StatementScenarioAxis" />
    <loc xlink:href="medp-20161231.xsd#medp_SummaryOfSignificantAccountingPoliciesTable" xlink:type="locator" xlink:label="medp_SummaryOfSignificantAccountingPoliciesTable" />
    <loc xlink:href="medp-20161231.xsd#medp_SummaryOfSignificantAccountingPoliciesLineItems" xlink:type="locator" xlink:label="medp_SummaryOfSignificantAccountingPoliciesLineItems" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="medp_SummaryOfSignificantAccountingPoliciesLineItems" xlink:to="medp_SummaryOfSignificantAccountingPoliciesTable" order="10010.00" priority="2" use="optional" xbrldt:contextElement="segment" xbrldt:closed="true" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="medp_SummaryOfSignificantAccountingPoliciesTable" xlink:to="us-gaap_StatementScenarioAxis" order="10040.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_StatementScenarioAxis" xlink:to="us-gaap_ScenarioUnspecifiedDomain" order="10060.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ScenarioUnspecifiedDomain" xlink:to="us-gaap_PredecessorMember" order="10080.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="medp_SummaryOfSignificantAccountingPoliciesTable" xlink:to="us-gaap_IncomeStatementLocationAxis" order="10090.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="us-gaap_IncomeStatementLocationAxis" xlink:to="us-gaap_IncomeStatementLocationDomain_2" order="10110.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_IncomeStatementLocationAxis" xlink:to="us-gaap_IncomeStatementLocationDomain" order="10110.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_IncomeStatementLocationDomain" xlink:to="us-gaap_OtherNonoperatingIncomeExpenseMember" order="10130.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="medp_SummaryOfSignificantAccountingPoliciesTable" xlink:to="us-gaap_RangeAxis" order="10140.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_RangeAxis" xlink:to="us-gaap_RangeMember" order="10160.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_RangeMember" xlink:to="us-gaap_MaximumMember" order="10180.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_IncomeStatementLocationDomain" xlink:to="us-gaap_SellingGeneralAndAdministrativeExpensesMember" order="10280.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="medp_SummaryOfSignificantAccountingPoliciesTable" xlink:to="us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis" order="10440.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis" xlink:to="us-gaap_AntidilutiveSecuritiesNameDomain_2" order="10460.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis" xlink:to="us-gaap_AntidilutiveSecuritiesNameDomain" order="10460.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_AntidilutiveSecuritiesNameDomain" xlink:to="us-gaap_EmployeeStockOptionMember" order="10480.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_AntidilutiveSecuritiesNameDomain" xlink:to="medp_RSAsAndRSUsMember" order="10500.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="medp_SummaryOfSignificantAccountingPoliciesTable" xlink:to="us-gaap_MortgageLoansOnRealEstateDescriptionTypeOfPropertyAxis" order="10610.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="us-gaap_MortgageLoansOnRealEstateDescriptionTypeOfPropertyAxis" xlink:to="us-gaap_MortgageLoansOnRealEstateNamePropertyTypeDomain_2" order="10630.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_MortgageLoansOnRealEstateDescriptionTypeOfPropertyAxis" xlink:to="us-gaap_MortgageLoansOnRealEstateNamePropertyTypeDomain" order="10630.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_MortgageLoansOnRealEstateNamePropertyTypeDomain" xlink:to="medp_PropertyInLeuvenBelgiumMember" order="10650.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="medp_SummaryOfSignificantAccountingPoliciesTable" xlink:to="us-gaap_PropertyPlantAndEquipmentByTypeAxis" order="10680.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="us-gaap_PropertyPlantAndEquipmentByTypeAxis" xlink:to="us-gaap_PropertyPlantAndEquipmentTypeDomain_2" order="10700.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_PropertyPlantAndEquipmentByTypeAxis" xlink:to="us-gaap_PropertyPlantAndEquipmentTypeDomain" order="10700.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_PropertyPlantAndEquipmentTypeDomain" xlink:to="medp_ComputerHardwareSoftwarePhoneAndMedicalImagingEquipmentMember" order="10720.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_PropertyPlantAndEquipmentTypeDomain" xlink:to="medp_FurnitureAndFixturesAndOtherEquipmentMember" order="10740.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_PropertyPlantAndEquipmentTypeDomain" xlink:to="us-gaap_BuildingMember" order="10760.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_PropertyPlantAndEquipmentTypeDomain" xlink:to="us-gaap_SoftwareAndSoftwareDevelopmentCostsMember" order="10780.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_RangeMember" xlink:to="us-gaap_MinimumMember" order="10830.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="medp_SummaryOfSignificantAccountingPoliciesLineItems" xlink:to="us-gaap_ForeignCurrencyTransactionGainLossBeforeTax" order="10950.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="medp_SummaryOfSignificantAccountingPoliciesLineItems" xlink:to="medp_SalesRebatesOnServiceRevenues" order="11140.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="medp_SummaryOfSignificantAccountingPoliciesLineItems" xlink:to="medp_NumberOfCustomersAccountedForMoreThanTenPercentOfAccountsReceivable" order="11330.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="medp_SummaryOfSignificantAccountingPoliciesLineItems" xlink:to="us-gaap_AdvertisingExpense" order="11440.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="medp_SummaryOfSignificantAccountingPoliciesLineItems" xlink:to="medp_PaymentForPreFundedStudyCostDisbursements" order="11630.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="medp_SummaryOfSignificantAccountingPoliciesLineItems" xlink:to="us-gaap_UndistributedEarningsOfForeignSubsidiaries" order="11820.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="medp_SummaryOfSignificantAccountingPoliciesLineItems" xlink:to="us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount" order="11890.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="medp_SummaryOfSignificantAccountingPoliciesLineItems" xlink:to="medp_FairValueAssetsTransfersBetweenLevel1Level2AndLevel3" order="12400.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="medp_SummaryOfSignificantAccountingPoliciesLineItems" xlink:to="us-gaap_PrepaidExpenseAndOtherAssetsCurrent" order="12590.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="medp_SummaryOfSignificantAccountingPoliciesLineItems" xlink:to="us-gaap_OtherAssetsNoncurrent" order="12630.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="medp_SummaryOfSignificantAccountingPoliciesLineItems" xlink:to="us-gaap_PropertyPlantAndEquipmentUsefulLife" order="12700.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="medp_SummaryOfSignificantAccountingPoliciesLineItems" xlink:to="us-gaap_FiniteLivedIntangibleAssetUsefulLife" order="13030.00" priority="2" use="optional" />
  </definitionLink>
  <roleRef roleURI="http://www.medpace.com/20161231/taxonomy/role/DisclosureSummaryOfSignificantAccountingPoliciesScheduleOfReconciliationOfDenominatorsAndAdditionalSharesThatAreExcludedFromCalculationOfEPSDetails" xlink:href="medp-20161231.xsd#Role_DisclosureSummaryOfSignificantAccountingPoliciesScheduleOfReconciliationOfDenominatorsAndAdditionalSharesThatAreExcludedFromCalculationOfEPSDetails" xlink:type="simple" />
  <definitionLink xlink:type="extended" xlink:role="http://www.medpace.com/20161231/taxonomy/role/DisclosureSummaryOfSignificantAccountingPoliciesScheduleOfReconciliationOfDenominatorsAndAdditionalSharesThatAreExcludedFromCalculationOfEPSDetails">
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_EarningsPerShareDiluted" xlink:type="locator" xlink:label="us-gaap_EarningsPerShareDiluted" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding" xlink:type="locator" xlink:label="us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_WeightedAverageNumberDilutedSharesOutstandingAdjustment" xlink:type="locator" xlink:label="us-gaap_WeightedAverageNumberDilutedSharesOutstandingAdjustment" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_EarningsPerShareBasic" xlink:type="locator" xlink:label="us-gaap_EarningsPerShareBasic" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_NetIncomeLossAvailableToCommonStockholdersBasic" xlink:type="locator" xlink:label="us-gaap_NetIncomeLossAvailableToCommonStockholdersBasic" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_UndistributedEarnings" xlink:type="locator" xlink:label="us-gaap_UndistributedEarnings" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_NetIncomeLoss" xlink:type="locator" xlink:label="us-gaap_NetIncomeLoss" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_EarningsPerShareBasicAbstract" xlink:type="locator" xlink:label="us-gaap_EarningsPerShareBasicAbstract" />
    <loc xlink:href="medp-20161231.xsd#medp_WeightedAverageNumberOfCommonAndRestrictedSharesOutstandingBasic" xlink:type="locator" xlink:label="medp_WeightedAverageNumberOfCommonAndRestrictedSharesOutstandingBasic" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_WeightedAverageNumberOfSharesOutstandingBasic" xlink:type="locator" xlink:label="us-gaap_WeightedAverageNumberOfSharesOutstandingBasic" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_WeightedAverageNumberOfSharesOutstandingBasicAbstract" xlink:type="locator" xlink:label="us-gaap_WeightedAverageNumberOfSharesOutstandingBasicAbstract" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_RestrictedStockMember" xlink:type="locator" xlink:label="us-gaap_RestrictedStockMember" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:type="locator" xlink:label="us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_2" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:type="locator" xlink:label="us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_AwardTypeAxis" xlink:type="locator" xlink:label="us-gaap_AwardTypeAxis" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_PredecessorMember" xlink:type="locator" xlink:label="us-gaap_PredecessorMember" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ScenarioUnspecifiedDomain" xlink:type="locator" xlink:label="us-gaap_ScenarioUnspecifiedDomain" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_StatementScenarioAxis" xlink:type="locator" xlink:label="us-gaap_StatementScenarioAxis" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_CommonStockMember" xlink:type="locator" xlink:label="us-gaap_CommonStockMember" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_EquityComponentDomain" xlink:type="locator" xlink:label="us-gaap_EquityComponentDomain" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_StatementEquityComponentsAxis" xlink:type="locator" xlink:label="us-gaap_StatementEquityComponentsAxis" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ScheduleOfAntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareTable" xlink:type="locator" xlink:label="us-gaap_ScheduleOfAntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareTable" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareLineItems" xlink:type="locator" xlink:label="us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareLineItems" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareLineItems" xlink:to="us-gaap_ScheduleOfAntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareTable" order="10030.00" priority="2" use="optional" xbrldt:contextElement="segment" xbrldt:closed="true" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="us-gaap_ScheduleOfAntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareTable" xlink:to="us-gaap_StatementEquityComponentsAxis" order="10060.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_StatementEquityComponentsAxis" xlink:to="us-gaap_EquityComponentDomain" order="10080.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_EquityComponentDomain" xlink:to="us-gaap_CommonStockMember" order="10100.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="us-gaap_ScheduleOfAntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareTable" xlink:to="us-gaap_StatementScenarioAxis" order="10130.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_StatementScenarioAxis" xlink:to="us-gaap_ScenarioUnspecifiedDomain" order="10150.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ScenarioUnspecifiedDomain" xlink:to="us-gaap_PredecessorMember" order="10170.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="us-gaap_ScheduleOfAntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareTable" xlink:to="us-gaap_AwardTypeAxis" order="10180.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="us-gaap_AwardTypeAxis" xlink:to="us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_2" order="10200.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_AwardTypeAxis" xlink:to="us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" order="10200.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:to="us-gaap_RestrictedStockMember" order="10220.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareLineItems" xlink:to="us-gaap_WeightedAverageNumberOfSharesOutstandingBasicAbstract" order="10270.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_WeightedAverageNumberOfSharesOutstandingBasicAbstract" xlink:to="us-gaap_WeightedAverageNumberOfSharesOutstandingBasic" order="10430.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_WeightedAverageNumberOfSharesOutstandingBasicAbstract" xlink:to="medp_WeightedAverageNumberOfCommonAndRestrictedSharesOutstandingBasic" order="10750.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareLineItems" xlink:to="us-gaap_EarningsPerShareBasicAbstract" order="10910.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_EarningsPerShareBasicAbstract" xlink:to="us-gaap_NetIncomeLoss" order="11070.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_EarningsPerShareBasicAbstract" xlink:to="us-gaap_UndistributedEarnings" order="11150.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_EarningsPerShareBasicAbstract" xlink:to="us-gaap_NetIncomeLossAvailableToCommonStockholdersBasic" order="11310.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_EarningsPerShareBasicAbstract" xlink:to="us-gaap_EarningsPerShareBasic" order="11470.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_EarningsPerShareBasicAbstract" xlink:to="us-gaap_WeightedAverageNumberDilutedSharesOutstandingAdjustment" order="11630.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_EarningsPerShareBasicAbstract" xlink:to="us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding" order="11790.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareLineItems" xlink:to="us-gaap_EarningsPerShareDiluted" order="11870.00" priority="2" use="optional" />
  </definitionLink>
  <roleRef roleURI="http://www.medpace.com/20161231/taxonomy/role/DisclosureAccountsReceivableAndUnbilledNetScheduleOfAllowanceForDoubtfulAccountActivityDetails" xlink:href="medp-20161231.xsd#Role_DisclosureAccountsReceivableAndUnbilledNetScheduleOfAllowanceForDoubtfulAccountActivityDetails" xlink:type="simple" />
  <definitionLink xlink:type="extended" xlink:role="http://www.medpace.com/20161231/taxonomy/role/DisclosureAccountsReceivableAndUnbilledNetScheduleOfAllowanceForDoubtfulAccountActivityDetails">
    <loc xlink:href="medp-20161231.xsd#medp_AllowanceForDoubtfulAccountsReceivableWriteOffsAndRecoveries" xlink:type="locator" xlink:label="medp_AllowanceForDoubtfulAccountsReceivableWriteOffsAndRecoveries" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ProvisionForDoubtfulAccounts" xlink:type="locator" xlink:label="us-gaap_ProvisionForDoubtfulAccounts" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_AllowanceForDoubtfulAccountsReceivableCurrent" xlink:type="locator" xlink:label="us-gaap_AllowanceForDoubtfulAccountsReceivableCurrent" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_PredecessorMember" xlink:type="locator" xlink:label="us-gaap_PredecessorMember" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ScenarioUnspecifiedDomain" xlink:type="locator" xlink:label="us-gaap_ScenarioUnspecifiedDomain" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_StatementScenarioAxis" xlink:type="locator" xlink:label="us-gaap_StatementScenarioAxis" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ScheduleOfAccountsNotesLoansAndFinancingReceivableTable" xlink:type="locator" xlink:label="us-gaap_ScheduleOfAccountsNotesLoansAndFinancingReceivableTable" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_AccountsNotesAndLoansReceivableLineItems" xlink:type="locator" xlink:label="us-gaap_AccountsNotesAndLoansReceivableLineItems" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="us-gaap_AccountsNotesAndLoansReceivableLineItems" xlink:to="us-gaap_ScheduleOfAccountsNotesLoansAndFinancingReceivableTable" order="10010.00" priority="2" use="optional" xbrldt:contextElement="segment" xbrldt:closed="true" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="us-gaap_ScheduleOfAccountsNotesLoansAndFinancingReceivableTable" xlink:to="us-gaap_StatementScenarioAxis" order="10040.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_StatementScenarioAxis" xlink:to="us-gaap_ScenarioUnspecifiedDomain" order="10060.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ScenarioUnspecifiedDomain" xlink:to="us-gaap_PredecessorMember" order="10080.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_AccountsNotesAndLoansReceivableLineItems" xlink:to="us-gaap_AllowanceForDoubtfulAccountsReceivableCurrent" order="10110.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_AccountsNotesAndLoansReceivableLineItems" xlink:to="us-gaap_ProvisionForDoubtfulAccounts" order="10250.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_AccountsNotesAndLoansReceivableLineItems" xlink:to="medp_AllowanceForDoubtfulAccountsReceivableWriteOffsAndRecoveries" order="10410.00" priority="2" use="optional" />
  </definitionLink>
  <roleRef roleURI="http://www.medpace.com/20161231/taxonomy/role/DisclosurePropertyAndEquipmentNetSummaryOfPropertyAndEquipmentNetDetails" xlink:href="medp-20161231.xsd#Role_DisclosurePropertyAndEquipmentNetSummaryOfPropertyAndEquipmentNetDetails" xlink:type="simple" />
  <definitionLink xlink:type="extended" xlink:role="http://www.medpace.com/20161231/taxonomy/role/DisclosurePropertyAndEquipmentNetSummaryOfPropertyAndEquipmentNetDetails">
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_PropertyPlantAndEquipmentNet" xlink:type="locator" xlink:label="us-gaap_PropertyPlantAndEquipmentNet" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment" xlink:type="locator" xlink:label="us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_PropertyPlantAndEquipmentGross" xlink:type="locator" xlink:label="us-gaap_PropertyPlantAndEquipmentGross" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ConstructionInProgressMember" xlink:type="locator" xlink:label="us-gaap_ConstructionInProgressMember" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_AssetUnderConstructionMember" xlink:type="locator" xlink:label="us-gaap_AssetUnderConstructionMember" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_BuildingMember" xlink:type="locator" xlink:label="us-gaap_BuildingMember" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ComputerEquipmentMember" xlink:type="locator" xlink:label="us-gaap_ComputerEquipmentMember" />
    <loc xlink:href="medp-20161231.xsd#medp_FurnitureAndFixturesAndLeaseholdImprovementsMember" xlink:type="locator" xlink:label="medp_FurnitureAndFixturesAndLeaseholdImprovementsMember" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_EquipmentMember" xlink:type="locator" xlink:label="us-gaap_EquipmentMember" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_LandMember" xlink:type="locator" xlink:label="us-gaap_LandMember" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_PropertyPlantAndEquipmentTypeDomain" xlink:type="locator" xlink:label="us-gaap_PropertyPlantAndEquipmentTypeDomain" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_PropertyPlantAndEquipmentByTypeAxis" xlink:type="locator" xlink:label="us-gaap_PropertyPlantAndEquipmentByTypeAxis" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ScheduleOfPropertyPlantAndEquipmentTable" xlink:type="locator" xlink:label="us-gaap_ScheduleOfPropertyPlantAndEquipmentTable" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_PropertyPlantAndEquipmentLineItems" xlink:type="locator" xlink:label="us-gaap_PropertyPlantAndEquipmentLineItems" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="us-gaap_PropertyPlantAndEquipmentLineItems" xlink:to="us-gaap_ScheduleOfPropertyPlantAndEquipmentTable" order="10030.00" priority="2" use="optional" xbrldt:contextElement="segment" xbrldt:closed="true" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="us-gaap_ScheduleOfPropertyPlantAndEquipmentTable" xlink:to="us-gaap_PropertyPlantAndEquipmentByTypeAxis" order="10060.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_PropertyPlantAndEquipmentByTypeAxis" xlink:to="us-gaap_PropertyPlantAndEquipmentTypeDomain" order="10080.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_PropertyPlantAndEquipmentTypeDomain" xlink:to="us-gaap_LandMember" order="10100.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_PropertyPlantAndEquipmentTypeDomain" xlink:to="us-gaap_EquipmentMember" order="10120.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_PropertyPlantAndEquipmentTypeDomain" xlink:to="medp_FurnitureAndFixturesAndLeaseholdImprovementsMember" order="10140.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_PropertyPlantAndEquipmentTypeDomain" xlink:to="us-gaap_ComputerEquipmentMember" order="10160.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_PropertyPlantAndEquipmentTypeDomain" xlink:to="us-gaap_BuildingMember" order="10180.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_PropertyPlantAndEquipmentTypeDomain" xlink:to="us-gaap_AssetUnderConstructionMember" order="10200.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_PropertyPlantAndEquipmentTypeDomain" xlink:to="us-gaap_ConstructionInProgressMember" order="10220.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_PropertyPlantAndEquipmentLineItems" xlink:to="us-gaap_PropertyPlantAndEquipmentGross" order="10250.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_PropertyPlantAndEquipmentLineItems" xlink:to="us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment" order="10890.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_PropertyPlantAndEquipmentLineItems" xlink:to="us-gaap_PropertyPlantAndEquipmentNet" order="10970.00" priority="2" use="optional" />
  </definitionLink>
  <roleRef roleURI="http://www.medpace.com/20161231/taxonomy/role/DisclosureGoodwillAndIntangibleAssetsAdditionalInformationDetails" xlink:href="medp-20161231.xsd#Role_DisclosureGoodwillAndIntangibleAssetsAdditionalInformationDetails" xlink:type="simple" />
  <definitionLink xlink:type="extended" xlink:role="http://www.medpace.com/20161231/taxonomy/role/DisclosureGoodwillAndIntangibleAssetsAdditionalInformationDetails">
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_IndefiniteLivedIntangibleAssetsExcludingGoodwill" xlink:type="locator" xlink:label="us-gaap_IndefiniteLivedIntangibleAssetsExcludingGoodwill" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_Goodwill" xlink:type="locator" xlink:label="us-gaap_Goodwill" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_Assets" xlink:type="locator" xlink:label="us-gaap_Assets" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_GoodwillImpairmentLoss" xlink:type="locator" xlink:label="us-gaap_GoodwillImpairmentLoss" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_FairValueInputsLevel3Member" xlink:type="locator" xlink:label="us-gaap_FairValueInputsLevel3Member" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain" xlink:type="locator" xlink:label="us-gaap_FairValueMeasurementsFairValueHierarchyDomain_2" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain" xlink:type="locator" xlink:label="us-gaap_FairValueMeasurementsFairValueHierarchyDomain" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_FairValueByFairValueHierarchyLevelAxis" xlink:type="locator" xlink:label="us-gaap_FairValueByFairValueHierarchyLevelAxis" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_FairValueMeasurementsNonrecurringMember" xlink:type="locator" xlink:label="us-gaap_FairValueMeasurementsNonrecurringMember" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_FairValueMeasurementFrequencyDomain" xlink:type="locator" xlink:label="us-gaap_FairValueMeasurementFrequencyDomain_2" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_FairValueMeasurementFrequencyDomain" xlink:type="locator" xlink:label="us-gaap_FairValueMeasurementFrequencyDomain" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_FairValueByMeasurementFrequencyAxis" xlink:type="locator" xlink:label="us-gaap_FairValueByMeasurementFrequencyAxis" />
    <loc xlink:href="medp-20161231.xsd#medp_GoodwillAndIntangibleAssetsTable" xlink:type="locator" xlink:label="medp_GoodwillAndIntangibleAssetsTable" />
    <loc xlink:href="medp-20161231.xsd#medp_GoodwillAndIntangibleAssetsLineItems" xlink:type="locator" xlink:label="medp_GoodwillAndIntangibleAssetsLineItems" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="medp_GoodwillAndIntangibleAssetsLineItems" xlink:to="medp_GoodwillAndIntangibleAssetsTable" order="10010.00" priority="2" use="optional" xbrldt:contextElement="segment" xbrldt:closed="true" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="medp_GoodwillAndIntangibleAssetsTable" xlink:to="us-gaap_FairValueByMeasurementFrequencyAxis" order="10040.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="us-gaap_FairValueByMeasurementFrequencyAxis" xlink:to="us-gaap_FairValueMeasurementFrequencyDomain_2" order="10060.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_FairValueByMeasurementFrequencyAxis" xlink:to="us-gaap_FairValueMeasurementFrequencyDomain" order="10060.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_FairValueMeasurementFrequencyDomain" xlink:to="us-gaap_FairValueMeasurementsNonrecurringMember" order="10080.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="medp_GoodwillAndIntangibleAssetsTable" xlink:to="us-gaap_FairValueByFairValueHierarchyLevelAxis" order="10130.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="us-gaap_FairValueByFairValueHierarchyLevelAxis" xlink:to="us-gaap_FairValueMeasurementsFairValueHierarchyDomain_2" order="10150.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_FairValueByFairValueHierarchyLevelAxis" xlink:to="us-gaap_FairValueMeasurementsFairValueHierarchyDomain" order="10150.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_FairValueMeasurementsFairValueHierarchyDomain" xlink:to="us-gaap_FairValueInputsLevel3Member" order="10170.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="medp_GoodwillAndIntangibleAssetsLineItems" xlink:to="us-gaap_GoodwillImpairmentLoss" order="10240.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="medp_GoodwillAndIntangibleAssetsLineItems" xlink:to="us-gaap_Assets" order="10310.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="medp_GoodwillAndIntangibleAssetsLineItems" xlink:to="us-gaap_Goodwill" order="10350.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="medp_GoodwillAndIntangibleAssetsLineItems" xlink:to="us-gaap_IndefiniteLivedIntangibleAssetsExcludingGoodwill" order="10390.00" priority="2" use="optional" />
  </definitionLink>
  <roleRef roleURI="http://www.medpace.com/20161231/taxonomy/role/DisclosureGoodwillAndIntangibleAssetsScheduleOfIntangibleAssetsNetDetails" xlink:href="medp-20161231.xsd#Role_DisclosureGoodwillAndIntangibleAssetsScheduleOfIntangibleAssetsNetDetails" xlink:type="simple" />
  <definitionLink xlink:type="extended" xlink:role="http://www.medpace.com/20161231/taxonomy/role/DisclosureGoodwillAndIntangibleAssetsScheduleOfIntangibleAssetsNetDetails">
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_IndefiniteLivedIntangibleAssetsExcludingGoodwill" xlink:type="locator" xlink:label="us-gaap_IndefiniteLivedIntangibleAssetsExcludingGoodwill" />
    <loc xlink:href="medp-20161231.xsd#medp_IndefiniteLivedIntangibleAssetsAccumulatedAmortization" xlink:type="locator" xlink:label="medp_IndefiniteLivedIntangibleAssetsAccumulatedAmortization" />
    <loc xlink:href="medp-20161231.xsd#medp_IndefiniteLivedIntangibleAssetsGross" xlink:type="locator" xlink:label="medp_IndefiniteLivedIntangibleAssetsGross" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_IntangibleAssetsNetExcludingGoodwill" xlink:type="locator" xlink:label="us-gaap_IntangibleAssetsNetExcludingGoodwill" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization" xlink:type="locator" xlink:label="us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsGross" xlink:type="locator" xlink:label="us-gaap_FiniteLivedIntangibleAssetsGross" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_TradeNamesMember" xlink:type="locator" xlink:label="us-gaap_TradeNamesMember" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_IndefiniteLivedIntangibleAssetsMajorClassNameDomain" xlink:type="locator" xlink:label="us-gaap_IndefiniteLivedIntangibleAssetsMajorClassNameDomain_2" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_IndefiniteLivedIntangibleAssetsMajorClassNameDomain" xlink:type="locator" xlink:label="us-gaap_IndefiniteLivedIntangibleAssetsMajorClassNameDomain" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_IndefiniteLivedIntangibleAssetsByMajorClassAxis" xlink:type="locator" xlink:label="us-gaap_IndefiniteLivedIntangibleAssetsByMajorClassAxis" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_OtherIntangibleAssetsMember" xlink:type="locator" xlink:label="us-gaap_OtherIntangibleAssetsMember" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_DevelopedTechnologyRightsMember" xlink:type="locator" xlink:label="us-gaap_DevelopedTechnologyRightsMember" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_CustomerRelationshipsMember" xlink:type="locator" xlink:label="us-gaap_CustomerRelationshipsMember" />
    <loc xlink:href="medp-20161231.xsd#medp_BacklogMember" xlink:type="locator" xlink:label="medp_BacklogMember" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain" xlink:type="locator" xlink:label="us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_2" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain" xlink:type="locator" xlink:label="us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis" xlink:type="locator" xlink:label="us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis" />
    <loc xlink:href="medp-20161231.xsd#medp_ScheduleOfFiniteAndIndefiniteLivedIntangibleAssetsTable" xlink:type="locator" xlink:label="medp_ScheduleOfFiniteAndIndefiniteLivedIntangibleAssetsTable" />
    <loc xlink:href="medp-20161231.xsd#medp_ScheduleOfFiniteAndIndefiniteLivedIntangibleAssetsLineItems" xlink:type="locator" xlink:label="medp_ScheduleOfFiniteAndIndefiniteLivedIntangibleAssetsLineItems" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="medp_ScheduleOfFiniteAndIndefiniteLivedIntangibleAssetsLineItems" xlink:to="medp_ScheduleOfFiniteAndIndefiniteLivedIntangibleAssetsTable" order="10030.00" priority="2" use="optional" xbrldt:contextElement="segment" xbrldt:closed="true" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="medp_ScheduleOfFiniteAndIndefiniteLivedIntangibleAssetsTable" xlink:to="us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis" order="10060.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis" xlink:to="us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_2" order="10080.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis" xlink:to="us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain" order="10080.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain" xlink:to="medp_BacklogMember" order="10100.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain" xlink:to="us-gaap_CustomerRelationshipsMember" order="10120.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain" xlink:to="us-gaap_DevelopedTechnologyRightsMember" order="10140.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain" xlink:to="us-gaap_OtherIntangibleAssetsMember" order="10160.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="medp_ScheduleOfFiniteAndIndefiniteLivedIntangibleAssetsTable" xlink:to="us-gaap_IndefiniteLivedIntangibleAssetsByMajorClassAxis" order="10250.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="us-gaap_IndefiniteLivedIntangibleAssetsByMajorClassAxis" xlink:to="us-gaap_IndefiniteLivedIntangibleAssetsMajorClassNameDomain_2" order="10270.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_IndefiniteLivedIntangibleAssetsByMajorClassAxis" xlink:to="us-gaap_IndefiniteLivedIntangibleAssetsMajorClassNameDomain" order="10270.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_IndefiniteLivedIntangibleAssetsMajorClassNameDomain" xlink:to="us-gaap_TradeNamesMember" order="10290.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="medp_ScheduleOfFiniteAndIndefiniteLivedIntangibleAssetsLineItems" xlink:to="us-gaap_FiniteLivedIntangibleAssetsGross" order="10340.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="medp_ScheduleOfFiniteAndIndefiniteLivedIntangibleAssetsLineItems" xlink:to="us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization" order="10740.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="medp_ScheduleOfFiniteAndIndefiniteLivedIntangibleAssetsLineItems" xlink:to="us-gaap_IntangibleAssetsNetExcludingGoodwill" order="11140.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="medp_ScheduleOfFiniteAndIndefiniteLivedIntangibleAssetsLineItems" xlink:to="medp_IndefiniteLivedIntangibleAssetsGross" order="11530.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="medp_ScheduleOfFiniteAndIndefiniteLivedIntangibleAssetsLineItems" xlink:to="medp_IndefiniteLivedIntangibleAssetsAccumulatedAmortization" order="11610.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="medp_ScheduleOfFiniteAndIndefiniteLivedIntangibleAssetsLineItems" xlink:to="us-gaap_IndefiniteLivedIntangibleAssetsExcludingGoodwill" order="11690.00" priority="2" use="optional" />
  </definitionLink>
  <roleRef roleURI="http://www.medpace.com/20161231/taxonomy/role/DisclosureDebtScheduleOfDebtDetails" xlink:href="medp-20161231.xsd#Role_DisclosureDebtScheduleOfDebtDetails" xlink:type="simple" />
  <definitionLink xlink:type="extended" xlink:role="http://www.medpace.com/20161231/taxonomy/role/DisclosureDebtScheduleOfDebtDetails">
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_LongTermDebtNoncurrent" xlink:type="locator" xlink:label="us-gaap_LongTermDebtNoncurrent" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_LongTermDebtCurrent" xlink:type="locator" xlink:label="us-gaap_LongTermDebtCurrent" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_UnamortizedDebtIssuanceExpense" xlink:type="locator" xlink:label="us-gaap_UnamortizedDebtIssuanceExpense" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_DebtInstrumentUnamortizedDiscount" xlink:type="locator" xlink:label="us-gaap_DebtInstrumentUnamortizedDiscount" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_DebtInstrumentCarryingAmount" xlink:type="locator" xlink:label="us-gaap_DebtInstrumentCarryingAmount" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_CapitalLeaseObligationsMember" xlink:type="locator" xlink:label="us-gaap_CapitalLeaseObligationsMember" />
    <loc xlink:href="medp-20161231.xsd#medp_TermLoanMember" xlink:type="locator" xlink:label="medp_TermLoanMember" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_LongtermDebtTypeDomain" xlink:type="locator" xlink:label="us-gaap_LongtermDebtTypeDomain" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_LongtermDebtTypeAxis" xlink:type="locator" xlink:label="us-gaap_LongtermDebtTypeAxis" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_DebtInstrumentTable" xlink:type="locator" xlink:label="us-gaap_DebtInstrumentTable" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_DebtInstrumentLineItems" xlink:type="locator" xlink:label="us-gaap_DebtInstrumentLineItems" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="us-gaap_DebtInstrumentLineItems" xlink:to="us-gaap_DebtInstrumentTable" order="10050.00" priority="2" use="optional" xbrldt:contextElement="segment" xbrldt:closed="true" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="us-gaap_DebtInstrumentTable" xlink:to="us-gaap_LongtermDebtTypeAxis" order="10080.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_LongtermDebtTypeAxis" xlink:to="us-gaap_LongtermDebtTypeDomain" order="10100.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_LongtermDebtTypeDomain" xlink:to="medp_TermLoanMember" order="10120.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_LongtermDebtTypeDomain" xlink:to="us-gaap_CapitalLeaseObligationsMember" order="10140.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_DebtInstrumentLineItems" xlink:to="us-gaap_DebtInstrumentCarryingAmount" order="10170.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_DebtInstrumentLineItems" xlink:to="us-gaap_DebtInstrumentUnamortizedDiscount" order="10410.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_DebtInstrumentLineItems" xlink:to="us-gaap_UnamortizedDebtIssuanceExpense" order="10490.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_DebtInstrumentLineItems" xlink:to="us-gaap_LongTermDebtCurrent" order="10570.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_DebtInstrumentLineItems" xlink:to="us-gaap_LongTermDebtNoncurrent" order="10630.00" priority="2" use="optional" />
  </definitionLink>
  <roleRef roleURI="http://www.medpace.com/20161231/taxonomy/role/DisclosureDebtAdditionalInformationDetails" xlink:href="medp-20161231.xsd#Role_DisclosureDebtAdditionalInformationDetails" xlink:type="simple" />
  <definitionLink xlink:type="extended" xlink:role="http://www.medpace.com/20161231/taxonomy/role/DisclosureDebtAdditionalInformationDetails">
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_DebtInstrumentInterestRateStatedPercentage" xlink:type="locator" xlink:label="us-gaap_DebtInstrumentInterestRateStatedPercentage" />
    <loc xlink:href="medp-20161231.xsd#medp_DebtInstrumentInterestRateDeemedPercentage" xlink:type="locator" xlink:label="medp_DebtInstrumentInterestRateDeemedPercentage" />
    <loc xlink:href="medp-20161231.xsd#medp_LineOfCreditFacilityExpirationYear" xlink:type="locator" xlink:label="medp_LineOfCreditFacilityExpirationYear" />
    <loc xlink:href="medp-20161231.xsd#medp_DebtInstrumentUnamortizedLoanOriginationFee" xlink:type="locator" xlink:label="medp_DebtInstrumentUnamortizedLoanOriginationFee" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_DebtInstrumentFeeAmount" xlink:type="locator" xlink:label="us-gaap_DebtInstrumentFeeAmount" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_GainsLossesOnExtinguishmentOfDebt" xlink:type="locator" xlink:label="us-gaap_GainsLossesOnExtinguishmentOfDebt" />
    <loc xlink:href="medp-20161231.xsd#medp_RatioOfConsolidatedEarningsBeforeInterestTaxDepreciationAndAmortizationToConsolidatedInterestExpense" xlink:type="locator" xlink:label="medp_RatioOfConsolidatedEarningsBeforeInterestTaxDepreciationAndAmortizationToConsolidatedInterestExpense" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_BusinessCombinationConsiderationTransferred1" xlink:type="locator" xlink:label="us-gaap_BusinessCombinationConsiderationTransferred1" />
    <loc xlink:href="medp-20161231.xsd#medp_RatioOfIndebtednessToEarningsBeforeInterestTaxDepreciationAndAmortization" xlink:type="locator" xlink:label="medp_RatioOfIndebtednessToEarningsBeforeInterestTaxDepreciationAndAmortization" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_CashAndCashEquivalentsAtCarryingValue" xlink:type="locator" xlink:label="us-gaap_CashAndCashEquivalentsAtCarryingValue" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_UnamortizedLoanCommitmentAndOriginationFeesAndUnamortizedDiscountsOrPremiums" xlink:type="locator" xlink:label="us-gaap_UnamortizedLoanCommitmentAndOriginationFeesAndUnamortizedDiscountsOrPremiums" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_LoanProcessingFee" xlink:type="locator" xlink:label="us-gaap_LoanProcessingFee" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_DebtInstrumentUnamortizedDiscount" xlink:type="locator" xlink:label="us-gaap_DebtInstrumentUnamortizedDiscount" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_LettersOfCreditOutstandingAmount" xlink:type="locator" xlink:label="us-gaap_LettersOfCreditOutstandingAmount" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_LineOfCreditFacilityCommitmentFeeAmount" xlink:type="locator" xlink:label="us-gaap_LineOfCreditFacilityCommitmentFeeAmount" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_LineOfCredit" xlink:type="locator" xlink:label="us-gaap_LineOfCredit" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_LineOfCreditFacilityUnusedCapacityCommitmentFeePercentage" xlink:type="locator" xlink:label="us-gaap_LineOfCreditFacilityUnusedCapacityCommitmentFeePercentage" />
    <loc xlink:href="medp-20161231.xsd#medp_DebtInstrumentNetLeverageRatio" xlink:type="locator" xlink:label="medp_DebtInstrumentNetLeverageRatio" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_DebtInstrumentBasisSpreadOnVariableRate1" xlink:type="locator" xlink:label="us-gaap_DebtInstrumentBasisSpreadOnVariableRate1" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_DebtInstrumentDescriptionOfVariableRateBasis" xlink:type="locator" xlink:label="us-gaap_DebtInstrumentDescriptionOfVariableRateBasis" />
    <loc xlink:href="medp-20161231.xsd#medp_LineOfCreditFacilityExpirationDates" xlink:type="locator" xlink:label="medp_LineOfCreditFacilityExpirationDates" />
    <loc xlink:href="medp-20161231.xsd#medp_DebtInstrumentPercentageOfFaceValueIssued" xlink:type="locator" xlink:label="medp_DebtInstrumentPercentageOfFaceValueIssued" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity" xlink:type="locator" xlink:label="us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_LongTermDebt" xlink:type="locator" xlink:label="us-gaap_LongTermDebt" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_LongTermDebtFairValue" xlink:type="locator" xlink:label="us-gaap_LongTermDebtFairValue" />
    <loc xlink:href="medp-20161231.xsd#medp_TwoThousandFourteenSeniorSecuredCreditFacilitiesIncurredInterestRateScenarioTwoMember" xlink:type="locator" xlink:label="medp_TwoThousandFourteenSeniorSecuredCreditFacilitiesIncurredInterestRateScenarioTwoMember" />
    <loc xlink:href="medp-20161231.xsd#medp_TwoThousandFourteenSeniorSecuredCreditFacilitiesIncurredInterestRateScenarioOneMember" xlink:type="locator" xlink:label="medp_TwoThousandFourteenSeniorSecuredCreditFacilitiesIncurredInterestRateScenarioOneMember" />
    <loc xlink:href="medp-20161231.xsd#medp_TwoThousandFourteenSeniorSecuredTermLoanFacilityMember" xlink:type="locator" xlink:label="medp_TwoThousandFourteenSeniorSecuredTermLoanFacilityMember" />
    <loc xlink:href="medp-20161231.xsd#medp_TwoThousandFourteenSeniorSecuredRevolvingCreditFacilityMember" xlink:type="locator" xlink:label="medp_TwoThousandFourteenSeniorSecuredRevolvingCreditFacilityMember" />
    <loc xlink:href="medp-20161231.xsd#medp_TwoThousandFourteenSeniorSecuredCreditFacilitiesMember" xlink:type="locator" xlink:label="medp_TwoThousandFourteenSeniorSecuredCreditFacilitiesMember" />
    <loc xlink:href="medp-20161231.xsd#medp_UnrestrictedMember" xlink:type="locator" xlink:label="medp_UnrestrictedMember" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_RestrictedCashAndCashEquivalentsCashAndCashEquivalentsMember" xlink:type="locator" xlink:label="us-gaap_RestrictedCashAndCashEquivalentsCashAndCashEquivalentsMember_2" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_RestrictedCashAndCashEquivalentsCashAndCashEquivalentsMember" xlink:type="locator" xlink:label="us-gaap_RestrictedCashAndCashEquivalentsCashAndCashEquivalentsMember" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_CashAndCashEquivalentsAxis" xlink:type="locator" xlink:label="us-gaap_CashAndCashEquivalentsAxis" />
    <loc xlink:href="medp-20161231.xsd#medp_ForeignMember" xlink:type="locator" xlink:label="medp_ForeignMember" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_SegmentGeographicalDomain" xlink:type="locator" xlink:label="us-gaap_SegmentGeographicalDomain_2" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_SegmentGeographicalDomain" xlink:type="locator" xlink:label="us-gaap_SegmentGeographicalDomain" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_StatementGeographicalAxis" xlink:type="locator" xlink:label="us-gaap_StatementGeographicalAxis" />
    <loc xlink:href="medp-20161231.xsd#medp_SeniorSecuredCreditFacilitiesBearInterestRateScenarioTwoMember" xlink:type="locator" xlink:label="medp_SeniorSecuredCreditFacilitiesBearInterestRateScenarioTwoMember" />
    <loc xlink:href="medp-20161231.xsd#medp_SeniorSecuredCreditFacilitiesBearInterestRateScenarioOneMember" xlink:type="locator" xlink:label="medp_SeniorSecuredCreditFacilitiesBearInterestRateScenarioOneMember" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ScenarioUnspecifiedDomain" xlink:type="locator" xlink:label="us-gaap_ScenarioUnspecifiedDomain" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_StatementScenarioAxis" xlink:type="locator" xlink:label="us-gaap_StatementScenarioAxis" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_BaseRateMember" xlink:type="locator" xlink:label="us-gaap_BaseRateMember" />
    <loc xlink:href="medp-20161231.xsd#medp_OneMonthAdjustedEurodollarMember" xlink:type="locator" xlink:label="medp_OneMonthAdjustedEurodollarMember" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_FederalFundsEffectiveSwapRateMember" xlink:type="locator" xlink:label="us-gaap_FederalFundsEffectiveSwapRateMember" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_EurodollarMember" xlink:type="locator" xlink:label="us-gaap_EurodollarMember" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_VariableRateDomain" xlink:type="locator" xlink:label="us-gaap_VariableRateDomain_2" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_VariableRateDomain" xlink:type="locator" xlink:label="us-gaap_VariableRateDomain" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_VariableRateAxis" xlink:type="locator" xlink:label="us-gaap_VariableRateAxis" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_MaximumMember" xlink:type="locator" xlink:label="us-gaap_MaximumMember" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_MinimumMember" xlink:type="locator" xlink:label="us-gaap_MinimumMember" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_RangeMember" xlink:type="locator" xlink:label="us-gaap_RangeMember" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_RangeAxis" xlink:type="locator" xlink:label="us-gaap_RangeAxis" />
    <loc xlink:href="medp-20161231.xsd#medp_SeniorSecuredTermLoanFacilityMember" xlink:type="locator" xlink:label="medp_SeniorSecuredTermLoanFacilityMember" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_RevolvingCreditFacilityMember" xlink:type="locator" xlink:label="us-gaap_RevolvingCreditFacilityMember" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_CreditFacilityDomain" xlink:type="locator" xlink:label="us-gaap_CreditFacilityDomain_2" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_CreditFacilityDomain" xlink:type="locator" xlink:label="us-gaap_CreditFacilityDomain" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_CreditFacilityAxis" xlink:type="locator" xlink:label="us-gaap_CreditFacilityAxis" />
    <loc xlink:href="medp-20161231.xsd#medp_SeniorSecuredCreditFacilitiesMember" xlink:type="locator" xlink:label="medp_SeniorSecuredCreditFacilitiesMember" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_DebtInstrumentNameDomain" xlink:type="locator" xlink:label="us-gaap_DebtInstrumentNameDomain_2" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_DebtInstrumentNameDomain" xlink:type="locator" xlink:label="us-gaap_DebtInstrumentNameDomain" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_DebtInstrumentAxis" xlink:type="locator" xlink:label="us-gaap_DebtInstrumentAxis" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_FairValueInputsLevel1Member" xlink:type="locator" xlink:label="us-gaap_FairValueInputsLevel1Member" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_FairValueInputsLevel2Member" xlink:type="locator" xlink:label="us-gaap_FairValueInputsLevel2Member" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain" xlink:type="locator" xlink:label="us-gaap_FairValueMeasurementsFairValueHierarchyDomain" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_FairValueByFairValueHierarchyLevelAxis" xlink:type="locator" xlink:label="us-gaap_FairValueByFairValueHierarchyLevelAxis" />
    <loc xlink:href="medp-20161231.xsd#medp_TermLoanMember" xlink:type="locator" xlink:label="medp_TermLoanMember" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_LongtermDebtTypeDomain" xlink:type="locator" xlink:label="us-gaap_LongtermDebtTypeDomain" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_LongtermDebtTypeAxis" xlink:type="locator" xlink:label="us-gaap_LongtermDebtTypeAxis" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_DebtInstrumentTable" xlink:type="locator" xlink:label="us-gaap_DebtInstrumentTable" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_DebtInstrumentLineItems" xlink:type="locator" xlink:label="us-gaap_DebtInstrumentLineItems" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="us-gaap_DebtInstrumentLineItems" xlink:to="us-gaap_DebtInstrumentTable" order="10010.00" priority="2" use="optional" xbrldt:contextElement="segment" xbrldt:closed="true" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="us-gaap_DebtInstrumentTable" xlink:to="us-gaap_LongtermDebtTypeAxis" order="10040.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_LongtermDebtTypeAxis" xlink:to="us-gaap_LongtermDebtTypeDomain" order="10060.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_LongtermDebtTypeDomain" xlink:to="medp_TermLoanMember" order="10080.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="us-gaap_DebtInstrumentTable" xlink:to="us-gaap_FairValueByFairValueHierarchyLevelAxis" order="10110.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_FairValueByFairValueHierarchyLevelAxis" xlink:to="us-gaap_FairValueMeasurementsFairValueHierarchyDomain" order="10130.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_FairValueMeasurementsFairValueHierarchyDomain" xlink:to="us-gaap_FairValueInputsLevel2Member" order="10150.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_FairValueMeasurementsFairValueHierarchyDomain" xlink:to="us-gaap_FairValueInputsLevel1Member" order="10170.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="us-gaap_DebtInstrumentTable" xlink:to="us-gaap_DebtInstrumentAxis" order="10180.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="us-gaap_DebtInstrumentAxis" xlink:to="us-gaap_DebtInstrumentNameDomain_2" order="10200.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_DebtInstrumentAxis" xlink:to="us-gaap_DebtInstrumentNameDomain" order="10200.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_DebtInstrumentNameDomain" xlink:to="medp_SeniorSecuredCreditFacilitiesMember" order="10220.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="us-gaap_DebtInstrumentTable" xlink:to="us-gaap_CreditFacilityAxis" order="10250.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="us-gaap_CreditFacilityAxis" xlink:to="us-gaap_CreditFacilityDomain_2" order="10270.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_CreditFacilityAxis" xlink:to="us-gaap_CreditFacilityDomain" order="10270.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_CreditFacilityDomain" xlink:to="us-gaap_RevolvingCreditFacilityMember" order="10290.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_LongtermDebtTypeDomain" xlink:to="medp_SeniorSecuredTermLoanFacilityMember" order="10340.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="us-gaap_DebtInstrumentTable" xlink:to="us-gaap_RangeAxis" order="10400.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_RangeAxis" xlink:to="us-gaap_RangeMember" order="10420.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_RangeMember" xlink:to="us-gaap_MinimumMember" order="10440.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_RangeMember" xlink:to="us-gaap_MaximumMember" order="10460.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="us-gaap_DebtInstrumentTable" xlink:to="us-gaap_VariableRateAxis" order="10590.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="us-gaap_VariableRateAxis" xlink:to="us-gaap_VariableRateDomain_2" order="10610.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_VariableRateAxis" xlink:to="us-gaap_VariableRateDomain" order="10610.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_VariableRateDomain" xlink:to="us-gaap_EurodollarMember" order="10630.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_VariableRateDomain" xlink:to="us-gaap_FederalFundsEffectiveSwapRateMember" order="10710.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_VariableRateDomain" xlink:to="medp_OneMonthAdjustedEurodollarMember" order="10730.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_VariableRateDomain" xlink:to="us-gaap_BaseRateMember" order="10750.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="us-gaap_DebtInstrumentTable" xlink:to="us-gaap_StatementScenarioAxis" order="10910.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_StatementScenarioAxis" xlink:to="us-gaap_ScenarioUnspecifiedDomain" order="10930.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ScenarioUnspecifiedDomain" xlink:to="medp_SeniorSecuredCreditFacilitiesBearInterestRateScenarioOneMember" order="10950.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ScenarioUnspecifiedDomain" xlink:to="medp_SeniorSecuredCreditFacilitiesBearInterestRateScenarioTwoMember" order="10970.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="us-gaap_DebtInstrumentTable" xlink:to="us-gaap_StatementGeographicalAxis" order="11720.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="us-gaap_StatementGeographicalAxis" xlink:to="us-gaap_SegmentGeographicalDomain_2" order="11740.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_StatementGeographicalAxis" xlink:to="us-gaap_SegmentGeographicalDomain" order="11740.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_SegmentGeographicalDomain" xlink:to="medp_ForeignMember" order="11760.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="us-gaap_DebtInstrumentTable" xlink:to="us-gaap_CashAndCashEquivalentsAxis" order="11770.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="us-gaap_CashAndCashEquivalentsAxis" xlink:to="us-gaap_RestrictedCashAndCashEquivalentsCashAndCashEquivalentsMember_2" order="11790.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_CashAndCashEquivalentsAxis" xlink:to="us-gaap_RestrictedCashAndCashEquivalentsCashAndCashEquivalentsMember" order="11790.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_RestrictedCashAndCashEquivalentsCashAndCashEquivalentsMember" xlink:to="medp_UnrestrictedMember" order="11810.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_DebtInstrumentNameDomain" xlink:to="medp_TwoThousandFourteenSeniorSecuredCreditFacilitiesMember" order="11930.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_LongtermDebtTypeDomain" xlink:to="medp_TwoThousandFourteenSeniorSecuredRevolvingCreditFacilityMember" order="12000.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_CreditFacilityDomain" xlink:to="medp_TwoThousandFourteenSeniorSecuredTermLoanFacilityMember" order="12050.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ScenarioUnspecifiedDomain" xlink:to="medp_TwoThousandFourteenSeniorSecuredCreditFacilitiesIncurredInterestRateScenarioOneMember" order="12580.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ScenarioUnspecifiedDomain" xlink:to="medp_TwoThousandFourteenSeniorSecuredCreditFacilitiesIncurredInterestRateScenarioTwoMember" order="12600.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_CreditFacilityDomain" xlink:to="medp_TwoThousandFourteenSeniorSecuredRevolvingCreditFacilityMember" order="12870.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_CreditFacilityDomain" xlink:to="medp_TwoThousandFourteenSeniorSecuredCreditFacilitiesMember" order="12980.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_DebtInstrumentNameDomain" xlink:to="medp_TwoThousandFourteenSeniorSecuredTermLoanFacilityMember" order="13070.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_DebtInstrumentNameDomain" xlink:to="medp_TwoThousandFourteenSeniorSecuredRevolvingCreditFacilityMember" order="13090.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_DebtInstrumentLineItems" xlink:to="us-gaap_LongTermDebtFairValue" order="13120.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_DebtInstrumentLineItems" xlink:to="us-gaap_LongTermDebt" order="13240.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_DebtInstrumentLineItems" xlink:to="us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity" order="13390.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_DebtInstrumentLineItems" xlink:to="medp_DebtInstrumentPercentageOfFaceValueIssued" order="13470.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_DebtInstrumentLineItems" xlink:to="medp_LineOfCreditFacilityExpirationDates" order="13530.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_DebtInstrumentLineItems" xlink:to="us-gaap_DebtInstrumentDescriptionOfVariableRateBasis" order="13640.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_DebtInstrumentLineItems" xlink:to="us-gaap_DebtInstrumentBasisSpreadOnVariableRate1" order="13680.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_DebtInstrumentLineItems" xlink:to="medp_DebtInstrumentNetLeverageRatio" order="13760.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_DebtInstrumentLineItems" xlink:to="us-gaap_LineOfCreditFacilityUnusedCapacityCommitmentFeePercentage" order="14230.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_DebtInstrumentLineItems" xlink:to="us-gaap_LineOfCredit" order="14510.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_DebtInstrumentLineItems" xlink:to="us-gaap_LineOfCreditFacilityCommitmentFeeAmount" order="14630.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_DebtInstrumentLineItems" xlink:to="us-gaap_LettersOfCreditOutstandingAmount" order="14750.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_DebtInstrumentLineItems" xlink:to="us-gaap_DebtInstrumentUnamortizedDiscount" order="14900.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_DebtInstrumentLineItems" xlink:to="us-gaap_LoanProcessingFee" order="14970.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_DebtInstrumentLineItems" xlink:to="us-gaap_UnamortizedLoanCommitmentAndOriginationFeesAndUnamortizedDiscountsOrPremiums" order="15010.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_DebtInstrumentLineItems" xlink:to="us-gaap_CashAndCashEquivalentsAtCarryingValue" order="15160.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_DebtInstrumentLineItems" xlink:to="medp_RatioOfIndebtednessToEarningsBeforeInterestTaxDepreciationAndAmortization" order="15240.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_DebtInstrumentLineItems" xlink:to="us-gaap_BusinessCombinationConsiderationTransferred1" order="15320.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_DebtInstrumentLineItems" xlink:to="medp_RatioOfConsolidatedEarningsBeforeInterestTaxDepreciationAndAmortizationToConsolidatedInterestExpense" order="15360.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_DebtInstrumentLineItems" xlink:to="us-gaap_GainsLossesOnExtinguishmentOfDebt" order="15430.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_DebtInstrumentLineItems" xlink:to="us-gaap_DebtInstrumentFeeAmount" order="15470.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_DebtInstrumentLineItems" xlink:to="medp_DebtInstrumentUnamortizedLoanOriginationFee" order="15510.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_DebtInstrumentLineItems" xlink:to="medp_LineOfCreditFacilityExpirationYear" order="15680.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_DebtInstrumentLineItems" xlink:to="medp_DebtInstrumentInterestRateDeemedPercentage" order="15950.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_DebtInstrumentLineItems" xlink:to="us-gaap_DebtInstrumentInterestRateStatedPercentage" order="17040.00" priority="2" use="optional" />
  </definitionLink>
  <roleRef roleURI="http://www.medpace.com/20161231/taxonomy/role/DisclosureCommitmentsContingenciesAndGuaranteesScheduleOfMinimumFutureLeasePaymentsDetails" xlink:href="medp-20161231.xsd#Role_DisclosureCommitmentsContingenciesAndGuaranteesScheduleOfMinimumFutureLeasePaymentsDetails" xlink:type="simple" />
  <definitionLink xlink:type="extended" xlink:role="http://www.medpace.com/20161231/taxonomy/role/DisclosureCommitmentsContingenciesAndGuaranteesScheduleOfMinimumFutureLeasePaymentsDetails">
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_OperatingLeasesFutureMinimumPaymentsDue" xlink:type="locator" xlink:label="us-gaap_OperatingLeasesFutureMinimumPaymentsDue" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_OperatingLeasesFutureMinimumPaymentsDueThereafter" xlink:type="locator" xlink:label="us-gaap_OperatingLeasesFutureMinimumPaymentsDueThereafter" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_OperatingLeasesFutureMinimumPaymentsDueInFiveYears" xlink:type="locator" xlink:label="us-gaap_OperatingLeasesFutureMinimumPaymentsDueInFiveYears" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_OperatingLeasesFutureMinimumPaymentsDueInFourYears" xlink:type="locator" xlink:label="us-gaap_OperatingLeasesFutureMinimumPaymentsDueInFourYears" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_OperatingLeasesFutureMinimumPaymentsDueInThreeYears" xlink:type="locator" xlink:label="us-gaap_OperatingLeasesFutureMinimumPaymentsDueInThreeYears" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_OperatingLeasesFutureMinimumPaymentsDueInTwoYears" xlink:type="locator" xlink:label="us-gaap_OperatingLeasesFutureMinimumPaymentsDueInTwoYears" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_OperatingLeasesFutureMinimumPaymentsDueCurrent" xlink:type="locator" xlink:label="us-gaap_OperatingLeasesFutureMinimumPaymentsDueCurrent" />
    <loc xlink:href="medp-20161231.xsd#medp_NonRelatedPartyMember" xlink:type="locator" xlink:label="medp_NonRelatedPartyMember" />
    <loc xlink:href="medp-20161231.xsd#medp_RelatedPartyMember" xlink:type="locator" xlink:label="medp_RelatedPartyMember" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_RelatedPartyDomain" xlink:type="locator" xlink:label="us-gaap_RelatedPartyDomain" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_RelatedPartyTransactionsByRelatedPartyAxis" xlink:type="locator" xlink:label="us-gaap_RelatedPartyTransactionsByRelatedPartyAxis" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable" xlink:type="locator" xlink:label="us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_RelatedPartyTransactionLineItems" xlink:type="locator" xlink:label="us-gaap_RelatedPartyTransactionLineItems" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="us-gaap_RelatedPartyTransactionLineItems" xlink:to="us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable" order="10070.00" priority="2" use="optional" xbrldt:contextElement="segment" xbrldt:closed="true" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable" xlink:to="us-gaap_RelatedPartyTransactionsByRelatedPartyAxis" order="10100.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_RelatedPartyTransactionsByRelatedPartyAxis" xlink:to="us-gaap_RelatedPartyDomain" order="10120.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_RelatedPartyDomain" xlink:to="medp_RelatedPartyMember" order="10140.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_RelatedPartyDomain" xlink:to="medp_NonRelatedPartyMember" order="10160.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_RelatedPartyTransactionLineItems" xlink:to="us-gaap_OperatingLeasesFutureMinimumPaymentsDueCurrent" order="10190.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_RelatedPartyTransactionLineItems" xlink:to="us-gaap_OperatingLeasesFutureMinimumPaymentsDueInTwoYears" order="10310.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_RelatedPartyTransactionLineItems" xlink:to="us-gaap_OperatingLeasesFutureMinimumPaymentsDueInThreeYears" order="10430.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_RelatedPartyTransactionLineItems" xlink:to="us-gaap_OperatingLeasesFutureMinimumPaymentsDueInFourYears" order="10550.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_RelatedPartyTransactionLineItems" xlink:to="us-gaap_OperatingLeasesFutureMinimumPaymentsDueInFiveYears" order="10670.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_RelatedPartyTransactionLineItems" xlink:to="us-gaap_OperatingLeasesFutureMinimumPaymentsDueThereafter" order="10790.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_RelatedPartyTransactionLineItems" xlink:to="us-gaap_OperatingLeasesFutureMinimumPaymentsDue" order="10910.00" priority="2" use="optional" />
  </definitionLink>
  <roleRef roleURI="http://www.medpace.com/20161231/taxonomy/role/DisclosureCommitmentsContingenciesAndGuaranteesAdditionalInformationDetails" xlink:href="medp-20161231.xsd#Role_DisclosureCommitmentsContingenciesAndGuaranteesAdditionalInformationDetails" xlink:type="simple" />
  <definitionLink xlink:type="extended" xlink:role="http://www.medpace.com/20161231/taxonomy/role/DisclosureCommitmentsContingenciesAndGuaranteesAdditionalInformationDetails">
    <loc xlink:href="medp-20161231.xsd#medp_BadDebtRecoveryExpense" xlink:type="locator" xlink:label="medp_BadDebtRecoveryExpense" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ProceedsFromLegalSettlements" xlink:type="locator" xlink:label="us-gaap_ProceedsFromLegalSettlements" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_LitigationSettlementAmount" xlink:type="locator" xlink:label="us-gaap_LitigationSettlementAmount" />
    <loc xlink:href="medp-20161231.xsd#medp_NonPaymentOutstandingAmount" xlink:type="locator" xlink:label="medp_NonPaymentOutstandingAmount" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_LongtermPurchaseCommitmentPeriod" xlink:type="locator" xlink:label="us-gaap_LongtermPurchaseCommitmentPeriod" />
    <loc xlink:href="medp-20161231.xsd#medp_PurchaseCommitmentsDiscountPercentage" xlink:type="locator" xlink:label="medp_PurchaseCommitmentsDiscountPercentage" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_LongTermPurchaseCommitmentAmount" xlink:type="locator" xlink:label="us-gaap_LongTermPurchaseCommitmentAmount" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_OperatingLeasesRentExpenseMinimumRentals" xlink:type="locator" xlink:label="us-gaap_OperatingLeasesRentExpenseMinimumRentals" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_NumberOfRealEstateProperties" xlink:type="locator" xlink:label="us-gaap_NumberOfRealEstateProperties" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_MinimumMember" xlink:type="locator" xlink:label="us-gaap_MinimumMember" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_RangeMember" xlink:type="locator" xlink:label="us-gaap_RangeMember" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_RangeAxis" xlink:type="locator" xlink:label="us-gaap_RangeAxis" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_SellingGeneralAndAdministrativeExpensesMember" xlink:type="locator" xlink:label="us-gaap_SellingGeneralAndAdministrativeExpensesMember" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_IncomeStatementLocationDomain" xlink:type="locator" xlink:label="us-gaap_IncomeStatementLocationDomain" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_IncomeStatementLocationAxis" xlink:type="locator" xlink:label="us-gaap_IncomeStatementLocationAxis" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_PredecessorMember" xlink:type="locator" xlink:label="us-gaap_PredecessorMember" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ScenarioUnspecifiedDomain" xlink:type="locator" xlink:label="us-gaap_ScenarioUnspecifiedDomain" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_StatementScenarioAxis" xlink:type="locator" xlink:label="us-gaap_StatementScenarioAxis" />
    <loc xlink:href="medp-20161231.xsd#medp_CommitmentsContingenciesAndGuaranteesDisclosureTable" xlink:type="locator" xlink:label="medp_CommitmentsContingenciesAndGuaranteesDisclosureTable" />
    <loc xlink:href="medp-20161231.xsd#medp_CommitmentsContingenciesAndGuaranteesLineItems" xlink:type="locator" xlink:label="medp_CommitmentsContingenciesAndGuaranteesLineItems" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="medp_CommitmentsContingenciesAndGuaranteesLineItems" xlink:to="medp_CommitmentsContingenciesAndGuaranteesDisclosureTable" order="10010.00" priority="2" use="optional" xbrldt:contextElement="segment" xbrldt:closed="true" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="medp_CommitmentsContingenciesAndGuaranteesDisclosureTable" xlink:to="us-gaap_StatementScenarioAxis" order="10040.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_StatementScenarioAxis" xlink:to="us-gaap_ScenarioUnspecifiedDomain" order="10060.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ScenarioUnspecifiedDomain" xlink:to="us-gaap_PredecessorMember" order="10080.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="medp_CommitmentsContingenciesAndGuaranteesDisclosureTable" xlink:to="us-gaap_IncomeStatementLocationAxis" order="10090.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_IncomeStatementLocationAxis" xlink:to="us-gaap_IncomeStatementLocationDomain" order="10110.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_IncomeStatementLocationDomain" xlink:to="us-gaap_SellingGeneralAndAdministrativeExpensesMember" order="10130.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="medp_CommitmentsContingenciesAndGuaranteesDisclosureTable" xlink:to="us-gaap_RangeAxis" order="10140.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_RangeAxis" xlink:to="us-gaap_RangeMember" order="10160.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_RangeMember" xlink:to="us-gaap_MinimumMember" order="10180.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="medp_CommitmentsContingenciesAndGuaranteesLineItems" xlink:to="us-gaap_NumberOfRealEstateProperties" order="10210.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="medp_CommitmentsContingenciesAndGuaranteesLineItems" xlink:to="us-gaap_OperatingLeasesRentExpenseMinimumRentals" order="10280.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="medp_CommitmentsContingenciesAndGuaranteesLineItems" xlink:to="us-gaap_LongTermPurchaseCommitmentAmount" order="10470.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="medp_CommitmentsContingenciesAndGuaranteesLineItems" xlink:to="medp_PurchaseCommitmentsDiscountPercentage" order="10570.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="medp_CommitmentsContingenciesAndGuaranteesLineItems" xlink:to="us-gaap_LongtermPurchaseCommitmentPeriod" order="10650.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="medp_CommitmentsContingenciesAndGuaranteesLineItems" xlink:to="medp_NonPaymentOutstandingAmount" order="10760.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="medp_CommitmentsContingenciesAndGuaranteesLineItems" xlink:to="us-gaap_LitigationSettlementAmount" order="10820.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="medp_CommitmentsContingenciesAndGuaranteesLineItems" xlink:to="us-gaap_ProceedsFromLegalSettlements" order="10880.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="medp_CommitmentsContingenciesAndGuaranteesLineItems" xlink:to="medp_BadDebtRecoveryExpense" order="10940.00" priority="2" use="optional" />
  </definitionLink>
  <roleRef roleURI="http://www.medpace.com/20161231/taxonomy/role/DisclosureCommitmentsContingenciesAndGuaranteesScheduleOfMinimumAnnualPaymentsRequiredInConjunctionWithLandlordLiabilityDetails" xlink:href="medp-20161231.xsd#Role_DisclosureCommitmentsContingenciesAndGuaranteesScheduleOfMinimumAnnualPaymentsRequiredInConjunctionWithLandlordLiabilityDetails" xlink:type="simple" />
  <definitionLink xlink:type="extended" xlink:role="http://www.medpace.com/20161231/taxonomy/role/DisclosureCommitmentsContingenciesAndGuaranteesScheduleOfMinimumAnnualPaymentsRequiredInConjunctionWithLandlordLiabilityDetails">
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_CapitalLeasesFutureMinimumPaymentsNetMinimumPayments1" xlink:type="locator" xlink:label="us-gaap_CapitalLeasesFutureMinimumPaymentsNetMinimumPayments1" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_CapitalLeasesFutureMinimumPaymentsDueThereafter" xlink:type="locator" xlink:label="us-gaap_CapitalLeasesFutureMinimumPaymentsDueThereafter" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_CapitalLeasesFutureMinimumPaymentsDueInFiveYears" xlink:type="locator" xlink:label="us-gaap_CapitalLeasesFutureMinimumPaymentsDueInFiveYears" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_CapitalLeasesFutureMinimumPaymentsDueInFourYears" xlink:type="locator" xlink:label="us-gaap_CapitalLeasesFutureMinimumPaymentsDueInFourYears" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_CapitalLeasesFutureMinimumPaymentsDueInThreeYears" xlink:type="locator" xlink:label="us-gaap_CapitalLeasesFutureMinimumPaymentsDueInThreeYears" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_CapitalLeasesFutureMinimumPaymentsDueInTwoYears" xlink:type="locator" xlink:label="us-gaap_CapitalLeasesFutureMinimumPaymentsDueInTwoYears" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_CapitalLeasesFutureMinimumPaymentsDueCurrent" xlink:type="locator" xlink:label="us-gaap_CapitalLeasesFutureMinimumPaymentsDueCurrent" />
    <loc xlink:href="medp-20161231.xsd#medp_InterestPaymentsMember" xlink:type="locator" xlink:label="medp_InterestPaymentsMember" />
    <loc xlink:href="medp-20161231.xsd#medp_RelatedPartyMember" xlink:type="locator" xlink:label="medp_RelatedPartyMember" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_RelatedPartyTransactionDomain" xlink:type="locator" xlink:label="us-gaap_RelatedPartyTransactionDomain_2" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_RelatedPartyTransactionDomain" xlink:type="locator" xlink:label="us-gaap_RelatedPartyTransactionDomain" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_RelatedPartyTransactionAxis" xlink:type="locator" xlink:label="us-gaap_RelatedPartyTransactionAxis" />
    <loc xlink:href="medp-20161231.xsd#medp_CommitmentsContingenciesAndGuaranteesDisclosureTable" xlink:type="locator" xlink:label="medp_CommitmentsContingenciesAndGuaranteesDisclosureTable" />
    <loc xlink:href="medp-20161231.xsd#medp_CommitmentsContingenciesAndGuaranteesLineItems" xlink:type="locator" xlink:label="medp_CommitmentsContingenciesAndGuaranteesLineItems" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="medp_CommitmentsContingenciesAndGuaranteesLineItems" xlink:to="medp_CommitmentsContingenciesAndGuaranteesDisclosureTable" order="10070.00" priority="2" use="optional" xbrldt:contextElement="segment" xbrldt:closed="true" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="medp_CommitmentsContingenciesAndGuaranteesDisclosureTable" xlink:to="us-gaap_RelatedPartyTransactionAxis" order="10100.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="us-gaap_RelatedPartyTransactionAxis" xlink:to="us-gaap_RelatedPartyTransactionDomain_2" order="10120.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_RelatedPartyTransactionAxis" xlink:to="us-gaap_RelatedPartyTransactionDomain" order="10120.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_RelatedPartyTransactionDomain" xlink:to="medp_RelatedPartyMember" order="10140.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_RelatedPartyTransactionDomain" xlink:to="medp_InterestPaymentsMember" order="10160.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="medp_CommitmentsContingenciesAndGuaranteesLineItems" xlink:to="us-gaap_CapitalLeasesFutureMinimumPaymentsDueCurrent" order="10190.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="medp_CommitmentsContingenciesAndGuaranteesLineItems" xlink:to="us-gaap_CapitalLeasesFutureMinimumPaymentsDueInTwoYears" order="10310.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="medp_CommitmentsContingenciesAndGuaranteesLineItems" xlink:to="us-gaap_CapitalLeasesFutureMinimumPaymentsDueInThreeYears" order="10430.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="medp_CommitmentsContingenciesAndGuaranteesLineItems" xlink:to="us-gaap_CapitalLeasesFutureMinimumPaymentsDueInFourYears" order="10550.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="medp_CommitmentsContingenciesAndGuaranteesLineItems" xlink:to="us-gaap_CapitalLeasesFutureMinimumPaymentsDueInFiveYears" order="10670.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="medp_CommitmentsContingenciesAndGuaranteesLineItems" xlink:to="us-gaap_CapitalLeasesFutureMinimumPaymentsDueThereafter" order="10790.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="medp_CommitmentsContingenciesAndGuaranteesLineItems" xlink:to="us-gaap_CapitalLeasesFutureMinimumPaymentsNetMinimumPayments1" order="10910.00" priority="2" use="optional" />
  </definitionLink>
  <roleRef roleURI="http://www.medpace.com/20161231/taxonomy/role/DisclosureShareholdersEquityAdditionalInformationDetails" xlink:href="medp-20161231.xsd#Role_DisclosureShareholdersEquityAdditionalInformationDetails" xlink:type="simple" />
  <definitionLink xlink:type="extended" xlink:role="http://www.medpace.com/20161231/taxonomy/role/DisclosureShareholdersEquityAdditionalInformationDetails">
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_EmployeeServiceShareBasedCompensationTaxBenefitFromCompensationExpense" xlink:type="locator" xlink:label="us-gaap_EmployeeServiceShareBasedCompensationTaxBenefitFromCompensationExpense" />
    <loc xlink:href="medp-20161231.xsd#medp_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsRemainingGrantsInPeriod" xlink:type="locator" xlink:label="medp_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsRemainingGrantsInPeriod" />
    <loc xlink:href="medp-20161231.xsd#medp_DeferredCompensationShareBasedArrangementsLiabilityCurrentAndNoncurrentShares" xlink:type="locator" xlink:label="medp_DeferredCompensationShareBasedArrangementsLiabilityCurrentAndNoncurrentShares" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardPlanModificationNumberOfEmployeesAffected" xlink:type="locator" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardPlanModificationNumberOfEmployeesAffected" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ProceedsFromStockOptionsExercised" xlink:type="locator" xlink:label="us-gaap_ProceedsFromStockOptionsExercised" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardAcceleratedVestingNumber" xlink:type="locator" xlink:label="us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardAcceleratedVestingNumber" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAuthorized" xlink:type="locator" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAuthorized" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_DeferredCompensationCashbasedArrangementsLiabilityClassifiedNoncurrent" xlink:type="locator" xlink:label="us-gaap_DeferredCompensationCashbasedArrangementsLiabilityClassifiedNoncurrent" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_DeferredCompensationShareBasedArrangementsLiabilityCurrent" xlink:type="locator" xlink:label="us-gaap_DeferredCompensationShareBasedArrangementsLiabilityCurrent" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_DeferredCompensationSharebasedArrangementsLiabilityCurrentAndNoncurrent" xlink:type="locator" xlink:label="us-gaap_DeferredCompensationSharebasedArrangementsLiabilityCurrentAndNoncurrent" />
    <loc xlink:href="medp-20161231.xsd#medp_DeferredCompensationSharebasedArrangementsLiabilityCurrentAndNoncurrentReclassifiedToAdditionalPaidInCapital" xlink:type="locator" xlink:label="medp_DeferredCompensationSharebasedArrangementsLiabilityCurrentAndNoncurrentReclassifiedToAdditionalPaidInCapital" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_AllocatedShareBasedCompensationExpense" xlink:type="locator" xlink:label="us-gaap_AllocatedShareBasedCompensationExpense" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardPlanModificationIncrementalCompensationCost" xlink:type="locator" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardPlanModificationIncrementalCompensationCost" />
    <loc xlink:href="medp-20161231.xsd#medp_NumberOfCurrentEmployeesHoldingUnvestedRestrictedAwards" xlink:type="locator" xlink:label="medp_NumberOfCurrentEmployeesHoldingUnvestedRestrictedAwards" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber" xlink:type="locator" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardDescription" xlink:type="locator" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardDescription" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod" xlink:type="locator" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod" />
    <loc xlink:href="medp-20161231.xsd#medp_ShareBasedCompensationArrangementByShareBasedPaymentAwardYearOfExpiration" xlink:type="locator" xlink:label="medp_ShareBasedCompensationArrangementByShareBasedPaymentAwardYearOfExpiration" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_CommonStockCapitalSharesReservedForFutureIssuance" xlink:type="locator" xlink:label="us-gaap_CommonStockCapitalSharesReservedForFutureIssuance" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingRights" xlink:type="locator" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingRights" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardAwardVestingRightsPercentage" xlink:type="locator" xlink:label="us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardAwardVestingRightsPercentage" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1" xlink:type="locator" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross" xlink:type="locator" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardExpirationPeriod" xlink:type="locator" xlink:label="us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardExpirationPeriod" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant" xlink:type="locator" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_PreferredStockSharesAuthorized" xlink:type="locator" xlink:label="us-gaap_PreferredStockSharesAuthorized" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_CommonStockSharesAuthorized" xlink:type="locator" xlink:label="us-gaap_CommonStockSharesAuthorized" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_EmployeeStockOptionMember" xlink:type="locator" xlink:label="us-gaap_EmployeeStockOptionMember" />
    <loc xlink:href="medp-20161231.xsd#medp_RestrictedSharesMember" xlink:type="locator" xlink:label="medp_RestrictedSharesMember" />
    <loc xlink:href="medp-20161231.xsd#medp_PredecessorEquityPlansMember" xlink:type="locator" xlink:label="medp_PredecessorEquityPlansMember" />
    <loc xlink:href="medp-20161231.xsd#medp_TwoThousandElevenStockOptionPlanMember" xlink:type="locator" xlink:label="medp_TwoThousandElevenStockOptionPlanMember" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_PredecessorMember" xlink:type="locator" xlink:label="us-gaap_PredecessorMember" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ScenarioUnspecifiedDomain" xlink:type="locator" xlink:label="us-gaap_ScenarioUnspecifiedDomain" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_StatementScenarioAxis" xlink:type="locator" xlink:label="us-gaap_StatementScenarioAxis" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_OtherNoncurrentLiabilitiesMember" xlink:type="locator" xlink:label="us-gaap_OtherNoncurrentLiabilitiesMember" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_OtherCurrentLiabilitiesMember" xlink:type="locator" xlink:label="us-gaap_OtherCurrentLiabilitiesMember" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_BalanceSheetLocationDomain" xlink:type="locator" xlink:label="us-gaap_BalanceSheetLocationDomain_2" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_BalanceSheetLocationDomain" xlink:type="locator" xlink:label="us-gaap_BalanceSheetLocationDomain" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_BalanceSheetLocationAxis" xlink:type="locator" xlink:label="us-gaap_BalanceSheetLocationAxis" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ShareBasedCompensationAwardTrancheTwoMember" xlink:type="locator" xlink:label="us-gaap_ShareBasedCompensationAwardTrancheTwoMember" />
    <loc xlink:href="medp-20161231.xsd#medp_FullyVestedSharesMember" xlink:type="locator" xlink:label="medp_FullyVestedSharesMember" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_MinimumMember" xlink:type="locator" xlink:label="us-gaap_MinimumMember" />
    <loc xlink:href="medp-20161231.xsd#medp_TwoThousandFourteenEquityIncentivePlanMember" xlink:type="locator" xlink:label="medp_TwoThousandFourteenEquityIncentivePlanMember" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_RestrictedStockMember" xlink:type="locator" xlink:label="us-gaap_RestrictedStockMember" />
    <loc xlink:href="medp-20161231.xsd#medp_RSAsAndRSUsMember" xlink:type="locator" xlink:label="medp_RSAsAndRSUsMember" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:type="locator" xlink:label="us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_AwardTypeAxis" xlink:type="locator" xlink:label="us-gaap_AwardTypeAxis" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_MaximumMember" xlink:type="locator" xlink:label="us-gaap_MaximumMember" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_RangeMember" xlink:type="locator" xlink:label="us-gaap_RangeMember" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_RangeAxis" xlink:type="locator" xlink:label="us-gaap_RangeAxis" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ShareBasedCompensationAwardTrancheThreeMember" xlink:type="locator" xlink:label="us-gaap_ShareBasedCompensationAwardTrancheThreeMember" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ShareBasedCompensationAwardTrancheOneMember" xlink:type="locator" xlink:label="us-gaap_ShareBasedCompensationAwardTrancheOneMember" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_VestingDomain" xlink:type="locator" xlink:label="us-gaap_VestingDomain_2" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_VestingDomain" xlink:type="locator" xlink:label="us-gaap_VestingDomain" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_VestingAxis" xlink:type="locator" xlink:label="us-gaap_VestingAxis" />
    <loc xlink:href="medp-20161231.xsd#medp_TwoThousandSixteenIncentiveAwardPlanMember" xlink:type="locator" xlink:label="medp_TwoThousandSixteenIncentiveAwardPlanMember" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_PlanNameDomain" xlink:type="locator" xlink:label="us-gaap_PlanNameDomain_2" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_PlanNameDomain" xlink:type="locator" xlink:label="us-gaap_PlanNameDomain" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_PlanNameAxis" xlink:type="locator" xlink:label="us-gaap_PlanNameAxis" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" xlink:type="locator" xlink:label="us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:type="locator" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" order="10010.00" priority="2" use="optional" xbrldt:contextElement="segment" xbrldt:closed="true" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" xlink:to="us-gaap_PlanNameAxis" order="10040.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="us-gaap_PlanNameAxis" xlink:to="us-gaap_PlanNameDomain_2" order="10060.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_PlanNameAxis" xlink:to="us-gaap_PlanNameDomain" order="10060.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_PlanNameDomain" xlink:to="medp_TwoThousandSixteenIncentiveAwardPlanMember" order="10080.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" xlink:to="us-gaap_VestingAxis" order="10290.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="us-gaap_VestingAxis" xlink:to="us-gaap_VestingDomain_2" order="10310.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_VestingAxis" xlink:to="us-gaap_VestingDomain" order="10310.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_VestingDomain" xlink:to="us-gaap_ShareBasedCompensationAwardTrancheOneMember" order="10330.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_VestingDomain" xlink:to="us-gaap_ShareBasedCompensationAwardTrancheThreeMember" order="10370.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" xlink:to="us-gaap_RangeAxis" order="10420.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_RangeAxis" xlink:to="us-gaap_RangeMember" order="10440.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_RangeMember" xlink:to="us-gaap_MaximumMember" order="10460.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" xlink:to="us-gaap_AwardTypeAxis" order="10470.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_AwardTypeAxis" xlink:to="us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" order="10490.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:to="medp_RSAsAndRSUsMember" order="10510.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:to="us-gaap_RestrictedStockMember" order="10560.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_PlanNameDomain" xlink:to="medp_TwoThousandFourteenEquityIncentivePlanMember" order="10660.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_RangeMember" xlink:to="us-gaap_MinimumMember" order="10710.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:to="medp_FullyVestedSharesMember" order="10780.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_VestingDomain" xlink:to="us-gaap_ShareBasedCompensationAwardTrancheTwoMember" order="10830.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" xlink:to="us-gaap_BalanceSheetLocationAxis" order="11000.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="us-gaap_BalanceSheetLocationAxis" xlink:to="us-gaap_BalanceSheetLocationDomain_2" order="11020.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_BalanceSheetLocationAxis" xlink:to="us-gaap_BalanceSheetLocationDomain" order="11020.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_BalanceSheetLocationDomain" xlink:to="us-gaap_OtherCurrentLiabilitiesMember" order="11040.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_BalanceSheetLocationDomain" xlink:to="us-gaap_OtherNoncurrentLiabilitiesMember" order="11060.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" xlink:to="us-gaap_StatementScenarioAxis" order="11070.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_StatementScenarioAxis" xlink:to="us-gaap_ScenarioUnspecifiedDomain" order="11090.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ScenarioUnspecifiedDomain" xlink:to="us-gaap_PredecessorMember" order="11110.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_PlanNameDomain" xlink:to="medp_TwoThousandElevenStockOptionPlanMember" order="11160.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_PlanNameDomain" xlink:to="medp_PredecessorEquityPlansMember" order="11210.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:to="medp_RestrictedSharesMember" order="11260.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:to="us-gaap_EmployeeStockOptionMember" order="11430.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="us-gaap_CommonStockSharesAuthorized" order="11720.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="us-gaap_PreferredStockSharesAuthorized" order="11760.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant" order="11830.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardExpirationPeriod" order="11890.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross" order="11950.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1" order="12070.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardAwardVestingRightsPercentage" order="12190.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingRights" order="12250.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="us-gaap_CommonStockCapitalSharesReservedForFutureIssuance" order="12370.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="medp_ShareBasedCompensationArrangementByShareBasedPaymentAwardYearOfExpiration" order="12430.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod" order="13090.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardDescription" order="13240.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber" order="13310.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="medp_NumberOfCurrentEmployeesHoldingUnvestedRestrictedAwards" order="13350.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardPlanModificationIncrementalCompensationCost" order="13420.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="us-gaap_AllocatedShareBasedCompensationExpense" order="13460.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="medp_DeferredCompensationSharebasedArrangementsLiabilityCurrentAndNoncurrentReclassifiedToAdditionalPaidInCapital" order="13590.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="us-gaap_DeferredCompensationSharebasedArrangementsLiabilityCurrentAndNoncurrent" order="13650.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="us-gaap_DeferredCompensationShareBasedArrangementsLiabilityCurrent" order="13690.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="us-gaap_DeferredCompensationCashbasedArrangementsLiabilityClassifiedNoncurrent" order="13730.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAuthorized" order="13870.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardAcceleratedVestingNumber" order="13980.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="us-gaap_ProceedsFromStockOptionsExercised" order="14060.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardPlanModificationNumberOfEmployeesAffected" order="14100.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="medp_DeferredCompensationShareBasedArrangementsLiabilityCurrentAndNoncurrentShares" order="14290.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="medp_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsRemainingGrantsInPeriod" order="14410.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="us-gaap_EmployeeServiceShareBasedCompensationTaxBenefitFromCompensationExpense" order="14810.00" priority="2" use="optional" />
  </definitionLink>
  <roleRef roleURI="http://www.medpace.com/20161231/taxonomy/role/DisclosureShareholdersEquityScheduleOfWeightedAverageAssumptionsUsedInBSMModelToCalculateFairValueOfOptionsDetails" xlink:href="medp-20161231.xsd#Role_DisclosureShareholdersEquityScheduleOfWeightedAverageAssumptionsUsedInBSMModelToCalculateFairValueOfOptionsDetails" xlink:type="simple" />
  <definitionLink xlink:type="extended" xlink:role="http://www.medpace.com/20161231/taxonomy/role/DisclosureShareholdersEquityScheduleOfWeightedAverageAssumptionsUsedInBSMModelToCalculateFairValueOfOptionsDetails">
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedDividendRate" xlink:type="locator" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedDividendRate" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsRiskFreeInterestRate" xlink:type="locator" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsRiskFreeInterestRate" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedVolatilityRate" xlink:type="locator" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedVolatilityRate" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardFairValueAssumptionsExpectedTerm1" xlink:type="locator" xlink:label="us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardFairValueAssumptionsExpectedTerm1" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_PredecessorMember" xlink:type="locator" xlink:label="us-gaap_PredecessorMember" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ScenarioUnspecifiedDomain" xlink:type="locator" xlink:label="us-gaap_ScenarioUnspecifiedDomain" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_StatementScenarioAxis" xlink:type="locator" xlink:label="us-gaap_StatementScenarioAxis" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" xlink:type="locator" xlink:label="us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:type="locator" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" order="10010.00" priority="2" use="optional" xbrldt:contextElement="segment" xbrldt:closed="true" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" xlink:to="us-gaap_StatementScenarioAxis" order="10040.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_StatementScenarioAxis" xlink:to="us-gaap_ScenarioUnspecifiedDomain" order="10060.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ScenarioUnspecifiedDomain" xlink:to="us-gaap_PredecessorMember" order="10080.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardFairValueAssumptionsExpectedTerm1" order="10110.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedVolatilityRate" order="10270.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsRiskFreeInterestRate" order="10430.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedDividendRate" order="10590.00" priority="2" use="optional" />
  </definitionLink>
  <roleRef roleURI="http://www.medpace.com/20161231/taxonomy/role/DisclosureShareholdersEquityScheduleOfGrantDateFairValueAndStockBasedCompensationExpenseAllocatedDetails" xlink:href="medp-20161231.xsd#Role_DisclosureShareholdersEquityScheduleOfGrantDateFairValueAndStockBasedCompensationExpenseAllocatedDetails" xlink:type="simple" />
  <definitionLink xlink:type="extended" xlink:role="http://www.medpace.com/20161231/taxonomy/role/DisclosureShareholdersEquityScheduleOfGrantDateFairValueAndStockBasedCompensationExpenseAllocatedDetails">
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_AllocatedShareBasedCompensationExpense" xlink:type="locator" xlink:label="us-gaap_AllocatedShareBasedCompensationExpense" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue" xlink:type="locator" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageGrantDateFairValue" xlink:type="locator" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageGrantDateFairValue" />
    <loc xlink:href="medp-20161231.xsd#medp_RestrictedSharesMember" xlink:type="locator" xlink:label="medp_RestrictedSharesMember" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_EmployeeStockOptionMember" xlink:type="locator" xlink:label="us-gaap_EmployeeStockOptionMember" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:type="locator" xlink:label="us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_AwardTypeAxis" xlink:type="locator" xlink:label="us-gaap_AwardTypeAxis" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_SellingGeneralAndAdministrativeExpensesMember" xlink:type="locator" xlink:label="us-gaap_SellingGeneralAndAdministrativeExpensesMember" />
    <loc xlink:href="medp-20161231.xsd#medp_DirectCostsExcludingDepreciationAndAmortizationMember" xlink:type="locator" xlink:label="medp_DirectCostsExcludingDepreciationAndAmortizationMember" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_IncomeStatementLocationDomain" xlink:type="locator" xlink:label="us-gaap_IncomeStatementLocationDomain" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_IncomeStatementLocationAxis" xlink:type="locator" xlink:label="us-gaap_IncomeStatementLocationAxis" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_PredecessorMember" xlink:type="locator" xlink:label="us-gaap_PredecessorMember" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ScenarioUnspecifiedDomain" xlink:type="locator" xlink:label="us-gaap_ScenarioUnspecifiedDomain" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_StatementScenarioAxis" xlink:type="locator" xlink:label="us-gaap_StatementScenarioAxis" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ScheduleOfEmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsTable" xlink:type="locator" xlink:label="us-gaap_ScheduleOfEmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsTable" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_EmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsLineItems" xlink:type="locator" xlink:label="us-gaap_EmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsLineItems" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="us-gaap_EmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsLineItems" xlink:to="us-gaap_ScheduleOfEmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsTable" order="10010.00" priority="2" use="optional" xbrldt:contextElement="segment" xbrldt:closed="true" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="us-gaap_ScheduleOfEmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsTable" xlink:to="us-gaap_StatementScenarioAxis" order="10040.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_StatementScenarioAxis" xlink:to="us-gaap_ScenarioUnspecifiedDomain" order="10060.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ScenarioUnspecifiedDomain" xlink:to="us-gaap_PredecessorMember" order="10080.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="us-gaap_ScheduleOfEmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsTable" xlink:to="us-gaap_IncomeStatementLocationAxis" order="10090.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_IncomeStatementLocationAxis" xlink:to="us-gaap_IncomeStatementLocationDomain" order="10110.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_IncomeStatementLocationDomain" xlink:to="medp_DirectCostsExcludingDepreciationAndAmortizationMember" order="10130.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_IncomeStatementLocationDomain" xlink:to="us-gaap_SellingGeneralAndAdministrativeExpensesMember" order="10150.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="us-gaap_ScheduleOfEmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsTable" xlink:to="us-gaap_AwardTypeAxis" order="10160.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_AwardTypeAxis" xlink:to="us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" order="10180.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:to="us-gaap_EmployeeStockOptionMember" order="10200.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:to="medp_RestrictedSharesMember" order="10220.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_EmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsLineItems" xlink:to="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageGrantDateFairValue" order="10250.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_EmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsLineItems" xlink:to="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue" order="10390.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_EmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsLineItems" xlink:to="us-gaap_AllocatedShareBasedCompensationExpense" order="10530.00" priority="2" use="optional" />
  </definitionLink>
  <roleRef roleURI="http://www.medpace.com/20161231/taxonomy/role/DisclosureShareholdersEquityScheduleOfSuccessorAndPredecessorSStockOptionActivityDetails" xlink:href="medp-20161231.xsd#Role_DisclosureShareholdersEquityScheduleOfSuccessorAndPredecessorSStockOptionActivityDetails" xlink:type="simple" />
  <definitionLink xlink:type="extended" xlink:role="http://www.medpace.com/20161231/taxonomy/role/DisclosureShareholdersEquityScheduleOfSuccessorAndPredecessorSStockOptionActivityDetails">
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableWeightedAverageExercisePrice" xlink:type="locator" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableWeightedAverageExercisePrice" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsExpirationsInPeriodWeightedAverageExercisePrice" xlink:type="locator" xlink:label="us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsExpirationsInPeriodWeightedAverageExercisePrice" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsForfeituresInPeriodWeightedAverageExercisePrice" xlink:type="locator" xlink:label="us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsForfeituresInPeriodWeightedAverageExercisePrice" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsExercisesInPeriodWeightedAverageExercisePrice" xlink:type="locator" xlink:label="us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsExercisesInPeriodWeightedAverageExercisePrice" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageExercisePrice" xlink:type="locator" xlink:label="us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageExercisePrice" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice" xlink:type="locator" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableNumber" xlink:type="locator" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableNumber" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExpirationsInPeriod" xlink:type="locator" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExpirationsInPeriod" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsForfeituresInPeriod" xlink:type="locator" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsForfeituresInPeriod" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_StockIssuedDuringPeriodSharesStockOptionsExercised" xlink:type="locator" xlink:label="us-gaap_StockIssuedDuringPeriodSharesStockOptionsExercised" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross" xlink:type="locator" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber" xlink:type="locator" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_PredecessorMember" xlink:type="locator" xlink:label="us-gaap_PredecessorMember" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ScenarioUnspecifiedDomain" xlink:type="locator" xlink:label="us-gaap_ScenarioUnspecifiedDomain" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_StatementScenarioAxis" xlink:type="locator" xlink:label="us-gaap_StatementScenarioAxis" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" xlink:type="locator" xlink:label="us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:type="locator" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" order="10010.00" priority="2" use="optional" xbrldt:contextElement="segment" xbrldt:closed="true" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" xlink:to="us-gaap_StatementScenarioAxis" order="10040.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_StatementScenarioAxis" xlink:to="us-gaap_ScenarioUnspecifiedDomain" order="10060.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ScenarioUnspecifiedDomain" xlink:to="us-gaap_PredecessorMember" order="10080.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber" order="10160.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross" order="10320.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="us-gaap_StockIssuedDuringPeriodSharesStockOptionsExercised" order="10480.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsForfeituresInPeriod" order="10640.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExpirationsInPeriod" order="10800.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableNumber" order="11080.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice" order="11270.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageExercisePrice" order="11430.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsExercisesInPeriodWeightedAverageExercisePrice" order="11590.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsForfeituresInPeriodWeightedAverageExercisePrice" order="11750.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsExpirationsInPeriodWeightedAverageExercisePrice" order="11910.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableWeightedAverageExercisePrice" order="12190.00" priority="2" use="optional" />
  </definitionLink>
  <roleRef roleURI="http://www.medpace.com/20161231/taxonomy/role/DisclosureShareholdersEquityScheduleOfSuccessorAndPredecessorSRestrictedShareActivityDetails" xlink:href="medp-20161231.xsd#Role_DisclosureShareholdersEquityScheduleOfSuccessorAndPredecessorSRestrictedShareActivityDetails" xlink:type="simple" />
  <definitionLink xlink:type="extended" xlink:role="http://www.medpace.com/20161231/taxonomy/role/DisclosureShareholdersEquityScheduleOfSuccessorAndPredecessorSRestrictedShareActivityDetails">
    <loc xlink:href="medp-20161231.xsd#medp_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsCumulativeSharesVested" xlink:type="locator" xlink:label="medp_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsCumulativeSharesVested" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod" xlink:type="locator" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod" xlink:type="locator" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod" xlink:type="locator" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber" xlink:type="locator" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_PredecessorMember" xlink:type="locator" xlink:label="us-gaap_PredecessorMember" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ScenarioUnspecifiedDomain" xlink:type="locator" xlink:label="us-gaap_ScenarioUnspecifiedDomain" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_StatementScenarioAxis" xlink:type="locator" xlink:label="us-gaap_StatementScenarioAxis" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_RestrictedStockUnitsRSUMember" xlink:type="locator" xlink:label="us-gaap_RestrictedStockUnitsRSUMember" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:type="locator" xlink:label="us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_AwardTypeAxis" xlink:type="locator" xlink:label="us-gaap_AwardTypeAxis" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" xlink:type="locator" xlink:label="us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:type="locator" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" order="10010.00" priority="2" use="optional" xbrldt:contextElement="segment" xbrldt:closed="true" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" xlink:to="us-gaap_AwardTypeAxis" order="10040.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_AwardTypeAxis" xlink:to="us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" order="10060.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:to="us-gaap_RestrictedStockUnitsRSUMember" order="10080.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" xlink:to="us-gaap_StatementScenarioAxis" order="10190.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_StatementScenarioAxis" xlink:to="us-gaap_ScenarioUnspecifiedDomain" order="10210.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ScenarioUnspecifiedDomain" xlink:to="us-gaap_PredecessorMember" order="10230.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber" order="10260.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod" order="10420.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod" order="10580.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod" order="10740.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="medp_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsCumulativeSharesVested" order="11020.00" priority="2" use="optional" />
  </definitionLink>
  <roleRef roleURI="http://www.medpace.com/20161231/taxonomy/role/DisclosureShareholdersEquityScheduleOfStockOptionsExpectedToVestStockOptionsExercisableAndUnvestedRestrictedShareAwardsExpectedToVestDetails" xlink:href="medp-20161231.xsd#Role_DisclosureShareholdersEquityScheduleOfStockOptionsExpectedToVestStockOptionsExercisableAndUnvestedRestrictedShareAwardsExpectedToVestDetails" xlink:type="simple" />
  <definitionLink xlink:type="extended" xlink:role="http://www.medpace.com/20161231/taxonomy/role/DisclosureShareholdersEquityScheduleOfStockOptionsExpectedToVestStockOptionsExercisableAndUnvestedRestrictedShareAwardsExpectedToVestDetails">
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsExercisableWeightedAverageRemainingContractualTerm1" xlink:type="locator" xlink:label="us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsExercisableWeightedAverageRemainingContractualTerm1" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsVestedAndExpectedToVestExercisableWeightedAverageRemainingContractualTerm1" xlink:type="locator" xlink:label="us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsVestedAndExpectedToVestExercisableWeightedAverageRemainingContractualTerm1" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsVestedAndExpectedToVestOutstandingWeightedAverageRemainingContractualTerm1" xlink:type="locator" xlink:label="us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsVestedAndExpectedToVestOutstandingWeightedAverageRemainingContractualTerm1" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedShareBasedAwardsOtherThanOptions" xlink:type="locator" xlink:label="us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedShareBasedAwardsOtherThanOptions" />
    <loc xlink:href="medp-20161231.xsd#medp_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsExpectedToVestOutstandingNumber" xlink:type="locator" xlink:label="medp_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsExpectedToVestOutstandingNumber" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1" xlink:type="locator" xlink:label="us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedStockOptions" xlink:type="locator" xlink:label="us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedStockOptions" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsVestedAndExpectedToVestExercisableNumber" xlink:type="locator" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsVestedAndExpectedToVestExercisableNumber" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsVestedAndExpectedToVestOutstandingNumber" xlink:type="locator" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsVestedAndExpectedToVestOutstandingNumber" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableWeightedAverageExercisePrice" xlink:type="locator" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableWeightedAverageExercisePrice" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsVestedAndExpectedToVestExercisableWeightedAverageExercisePrice" xlink:type="locator" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsVestedAndExpectedToVestExercisableWeightedAverageExercisePrice" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_RestrictedStockMember" xlink:type="locator" xlink:label="us-gaap_RestrictedStockMember" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_EmployeeStockOptionMember" xlink:type="locator" xlink:label="us-gaap_EmployeeStockOptionMember" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:type="locator" xlink:label="us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_AwardTypeAxis" xlink:type="locator" xlink:label="us-gaap_AwardTypeAxis" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" xlink:type="locator" xlink:label="us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:type="locator" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" order="10010.00" priority="2" use="optional" xbrldt:contextElement="segment" xbrldt:closed="true" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" xlink:to="us-gaap_AwardTypeAxis" order="10040.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_AwardTypeAxis" xlink:to="us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" order="10060.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:to="us-gaap_EmployeeStockOptionMember" order="10080.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:to="us-gaap_RestrictedStockMember" order="10190.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsVestedAndExpectedToVestExercisableWeightedAverageExercisePrice" order="10260.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableWeightedAverageExercisePrice" order="10300.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsVestedAndExpectedToVestOutstandingNumber" order="10350.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsVestedAndExpectedToVestExercisableNumber" order="10430.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedStockOptions" order="10470.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1" order="10510.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="medp_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsExpectedToVestOutstandingNumber" order="10580.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedShareBasedAwardsOtherThanOptions" order="10660.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsVestedAndExpectedToVestOutstandingWeightedAverageRemainingContractualTerm1" order="10770.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsVestedAndExpectedToVestExercisableWeightedAverageRemainingContractualTerm1" order="10810.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsExercisableWeightedAverageRemainingContractualTerm1" order="10850.00" priority="2" use="optional" />
  </definitionLink>
  <roleRef roleURI="http://www.medpace.com/20161231/taxonomy/role/DisclosureShareholderSEquityScheduleOfAggregateIntrinsicValueOfStockOptionsExercisedFairValuesOfAwardsVestedAndShareBasedLiabilitiesSettledDetails" xlink:href="medp-20161231.xsd#Role_DisclosureShareholderSEquityScheduleOfAggregateIntrinsicValueOfStockOptionsExercisedFairValuesOfAwardsVestedAndShareBasedLiabilitiesSettledDetails" xlink:type="simple" />
  <definitionLink xlink:type="extended" xlink:role="http://www.medpace.com/20161231/taxonomy/role/DisclosureShareholderSEquityScheduleOfAggregateIntrinsicValueOfStockOptionsExercisedFairValuesOfAwardsVestedAndShareBasedLiabilitiesSettledDetails">
    <loc xlink:href="medp-20161231.xsd#medp_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsAggregateShareBasedLiabilitiesSettled" xlink:type="locator" xlink:label="medp_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsAggregateShareBasedLiabilitiesSettled" />
    <loc xlink:href="medp-20161231.xsd#medp_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsAggregateSettlementDateFairValueVested" xlink:type="locator" xlink:label="medp_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsAggregateSettlementDateFairValueVested" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodTotalFairValue" xlink:type="locator" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodTotalFairValue" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsVestedInPeriodFairValue1" xlink:type="locator" xlink:label="us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsVestedInPeriodFairValue1" />
    <loc xlink:href="medp-20161231.xsd#medp_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisedInPeriodIntrinsicValue" xlink:type="locator" xlink:label="medp_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisedInPeriodIntrinsicValue" />
    <loc xlink:href="medp-20161231.xsd#medp_RestrictedSharesMember" xlink:type="locator" xlink:label="medp_RestrictedSharesMember" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:type="locator" xlink:label="us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_AwardTypeAxis" xlink:type="locator" xlink:label="us-gaap_AwardTypeAxis" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_PredecessorMember" xlink:type="locator" xlink:label="us-gaap_PredecessorMember" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ScenarioUnspecifiedDomain" xlink:type="locator" xlink:label="us-gaap_ScenarioUnspecifiedDomain" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_StatementScenarioAxis" xlink:type="locator" xlink:label="us-gaap_StatementScenarioAxis" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" xlink:type="locator" xlink:label="us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:type="locator" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" order="10010.00" priority="2" use="optional" xbrldt:contextElement="segment" xbrldt:closed="true" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" xlink:to="us-gaap_StatementScenarioAxis" order="10040.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_StatementScenarioAxis" xlink:to="us-gaap_ScenarioUnspecifiedDomain" order="10060.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ScenarioUnspecifiedDomain" xlink:to="us-gaap_PredecessorMember" order="10080.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" xlink:to="us-gaap_AwardTypeAxis" order="10090.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_AwardTypeAxis" xlink:to="us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" order="10110.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:to="medp_RestrictedSharesMember" order="10130.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="medp_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisedInPeriodIntrinsicValue" order="10180.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsVestedInPeriodFairValue1" order="10340.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodTotalFairValue" order="10500.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="medp_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsAggregateSettlementDateFairValueVested" order="10660.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="medp_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsAggregateShareBasedLiabilitiesSettled" order="10820.00" priority="2" use="optional" />
  </definitionLink>
  <roleRef roleURI="http://www.medpace.com/20161231/taxonomy/role/DisclosureEmployeeBenefitPlansAdditionalInformationDetails" xlink:href="medp-20161231.xsd#Role_DisclosureEmployeeBenefitPlansAdditionalInformationDetails" xlink:type="simple" />
  <definitionLink xlink:type="extended" xlink:role="http://www.medpace.com/20161231/taxonomy/role/DisclosureEmployeeBenefitPlansAdditionalInformationDetails">
    <loc xlink:href="medp-20161231.xsd#medp_DefinedContributionPlanMinimumPeriodOfServiceRequiredForEmployerContributionsToFullyVest" xlink:type="locator" xlink:label="medp_DefinedContributionPlanMinimumPeriodOfServiceRequiredForEmployerContributionsToFullyVest" />
    <loc xlink:href="medp-20161231.xsd#medp_DefinedContributionPlanMinimumPeriodOfServiceRequiredForMatchingContributionEligibility" xlink:type="locator" xlink:label="medp_DefinedContributionPlanMinimumPeriodOfServiceRequiredForMatchingContributionEligibility" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_DefinedContributionPlanCostRecognized" xlink:type="locator" xlink:label="us-gaap_DefinedContributionPlanCostRecognized" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_DefinedContributionPlanMaximumAnnualContributionsPerEmployeePercent" xlink:type="locator" xlink:label="us-gaap_DefinedContributionPlanMaximumAnnualContributionsPerEmployeePercent" />
    <loc xlink:href="medp-20161231.xsd#medp_NonUSEmployeesMember" xlink:type="locator" xlink:label="medp_NonUSEmployeesMember" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember" xlink:type="locator" xlink:label="us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_PredecessorMember" xlink:type="locator" xlink:label="us-gaap_PredecessorMember" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ScenarioUnspecifiedDomain" xlink:type="locator" xlink:label="us-gaap_ScenarioUnspecifiedDomain" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_StatementScenarioAxis" xlink:type="locator" xlink:label="us-gaap_StatementScenarioAxis" />
    <loc xlink:href="medp-20161231.xsd#medp_USEmployeesMember" xlink:type="locator" xlink:label="medp_USEmployeesMember" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_DefinedBenefitPlansDomain" xlink:type="locator" xlink:label="us-gaap_DefinedBenefitPlansDomain_2" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_DefinedBenefitPlansDomain" xlink:type="locator" xlink:label="us-gaap_DefinedBenefitPlansDomain" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis" xlink:type="locator" xlink:label="us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_PensionPlansDefinedBenefitMember" xlink:type="locator" xlink:label="us-gaap_PensionPlansDefinedBenefitMember" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_DefinedContributionPlanTypeDomain" xlink:type="locator" xlink:label="us-gaap_DefinedContributionPlanTypeDomain_2" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_DefinedContributionPlanTypeDomain" xlink:type="locator" xlink:label="us-gaap_DefinedContributionPlanTypeDomain" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_DefinedContributionPlanTypeAxis" xlink:type="locator" xlink:label="us-gaap_DefinedContributionPlanTypeAxis" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ScheduleOfDefinedBenefitPlansDisclosuresTable" xlink:type="locator" xlink:label="us-gaap_ScheduleOfDefinedBenefitPlansDisclosuresTable" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_DefinedBenefitPlanDisclosureLineItems" xlink:type="locator" xlink:label="us-gaap_DefinedBenefitPlanDisclosureLineItems" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="us-gaap_DefinedBenefitPlanDisclosureLineItems" xlink:to="us-gaap_ScheduleOfDefinedBenefitPlansDisclosuresTable" order="10010.00" priority="2" use="optional" xbrldt:contextElement="segment" xbrldt:closed="true" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="us-gaap_ScheduleOfDefinedBenefitPlansDisclosuresTable" xlink:to="us-gaap_DefinedContributionPlanTypeAxis" order="10040.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="us-gaap_DefinedContributionPlanTypeAxis" xlink:to="us-gaap_DefinedContributionPlanTypeDomain_2" order="10060.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_DefinedContributionPlanTypeAxis" xlink:to="us-gaap_DefinedContributionPlanTypeDomain" order="10060.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_DefinedContributionPlanTypeDomain" xlink:to="us-gaap_PensionPlansDefinedBenefitMember" order="10080.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="us-gaap_ScheduleOfDefinedBenefitPlansDisclosuresTable" xlink:to="us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis" order="10090.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis" xlink:to="us-gaap_DefinedBenefitPlansDomain_2" order="10110.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis" xlink:to="us-gaap_DefinedBenefitPlansDomain" order="10110.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_DefinedBenefitPlansDomain" xlink:to="medp_USEmployeesMember" order="10130.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="us-gaap_ScheduleOfDefinedBenefitPlansDisclosuresTable" xlink:to="us-gaap_StatementScenarioAxis" order="10180.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_StatementScenarioAxis" xlink:to="us-gaap_ScenarioUnspecifiedDomain" order="10200.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ScenarioUnspecifiedDomain" xlink:to="us-gaap_PredecessorMember" order="10220.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_DefinedContributionPlanTypeDomain" xlink:to="us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember" order="10360.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_DefinedBenefitPlansDomain" xlink:to="medp_NonUSEmployeesMember" order="10460.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_DefinedBenefitPlanDisclosureLineItems" xlink:to="us-gaap_DefinedContributionPlanMaximumAnnualContributionsPerEmployeePercent" order="10490.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_DefinedBenefitPlanDisclosureLineItems" xlink:to="us-gaap_DefinedContributionPlanCostRecognized" order="10560.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_DefinedBenefitPlanDisclosureLineItems" xlink:to="medp_DefinedContributionPlanMinimumPeriodOfServiceRequiredForMatchingContributionEligibility" order="10720.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_DefinedBenefitPlanDisclosureLineItems" xlink:to="medp_DefinedContributionPlanMinimumPeriodOfServiceRequiredForEmployerContributionsToFullyVest" order="10820.00" priority="2" use="optional" />
  </definitionLink>
  <roleRef roleURI="http://www.medpace.com/20161231/taxonomy/role/DisclosureIncomeTaxesScheduleOfComponentsOfIncomeLossBeforeIncomeTaxesDetails" xlink:href="medp-20161231.xsd#Role_DisclosureIncomeTaxesScheduleOfComponentsOfIncomeLossBeforeIncomeTaxesDetails" xlink:type="simple" />
  <definitionLink xlink:type="extended" xlink:role="http://www.medpace.com/20161231/taxonomy/role/DisclosureIncomeTaxesScheduleOfComponentsOfIncomeLossBeforeIncomeTaxesDetails">
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest" xlink:type="locator" xlink:label="us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesForeign" xlink:type="locator" xlink:label="us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesForeign" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesDomestic" xlink:type="locator" xlink:label="us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesDomestic" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_PredecessorMember" xlink:type="locator" xlink:label="us-gaap_PredecessorMember" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ScenarioUnspecifiedDomain" xlink:type="locator" xlink:label="us-gaap_ScenarioUnspecifiedDomain" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_StatementScenarioAxis" xlink:type="locator" xlink:label="us-gaap_StatementScenarioAxis" />
    <loc xlink:href="medp-20161231.xsd#medp_IncomeTaxDisclosureTable" xlink:type="locator" xlink:label="medp_IncomeTaxDisclosureTable" />
    <loc xlink:href="medp-20161231.xsd#medp_IncomeTaxDisclosureLineItems" xlink:type="locator" xlink:label="medp_IncomeTaxDisclosureLineItems" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="medp_IncomeTaxDisclosureLineItems" xlink:to="medp_IncomeTaxDisclosureTable" order="10030.00" priority="2" use="optional" xbrldt:contextElement="segment" xbrldt:closed="true" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="medp_IncomeTaxDisclosureTable" xlink:to="us-gaap_StatementScenarioAxis" order="10060.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_StatementScenarioAxis" xlink:to="us-gaap_ScenarioUnspecifiedDomain" order="10080.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ScenarioUnspecifiedDomain" xlink:to="us-gaap_PredecessorMember" order="10100.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="medp_IncomeTaxDisclosureLineItems" xlink:to="us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesDomestic" order="10130.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="medp_IncomeTaxDisclosureLineItems" xlink:to="us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesForeign" order="10290.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="medp_IncomeTaxDisclosureLineItems" xlink:to="us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest" order="10450.00" priority="2" use="optional" />
  </definitionLink>
  <roleRef roleURI="http://www.medpace.com/20161231/taxonomy/role/DisclosureIncomeTaxesScheduleOfIncomeTaxProvisionBenefitDetails" xlink:href="medp-20161231.xsd#Role_DisclosureIncomeTaxesScheduleOfIncomeTaxProvisionBenefitDetails" xlink:type="simple" />
  <definitionLink xlink:type="extended" xlink:role="http://www.medpace.com/20161231/taxonomy/role/DisclosureIncomeTaxesScheduleOfIncomeTaxProvisionBenefitDetails">
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_IncomeTaxExpenseBenefit" xlink:type="locator" xlink:label="us-gaap_IncomeTaxExpenseBenefit" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_DeferredIncomeTaxesAndTaxCredits" xlink:type="locator" xlink:label="us-gaap_DeferredIncomeTaxesAndTaxCredits" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_CurrentIncomeTaxExpenseBenefit" xlink:type="locator" xlink:label="us-gaap_CurrentIncomeTaxExpenseBenefit" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ForeignIncomeTaxExpenseBenefitContinuingOperations" xlink:type="locator" xlink:label="us-gaap_ForeignIncomeTaxExpenseBenefitContinuingOperations" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_DeferredForeignIncomeTaxExpenseBenefit" xlink:type="locator" xlink:label="us-gaap_DeferredForeignIncomeTaxExpenseBenefit" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_CurrentForeignTaxExpenseBenefit" xlink:type="locator" xlink:label="us-gaap_CurrentForeignTaxExpenseBenefit" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_StateAndLocalIncomeTaxExpenseBenefitContinuingOperations" xlink:type="locator" xlink:label="us-gaap_StateAndLocalIncomeTaxExpenseBenefitContinuingOperations" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_DeferredStateAndLocalIncomeTaxExpenseBenefit" xlink:type="locator" xlink:label="us-gaap_DeferredStateAndLocalIncomeTaxExpenseBenefit" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_CurrentStateAndLocalTaxExpenseBenefit" xlink:type="locator" xlink:label="us-gaap_CurrentStateAndLocalTaxExpenseBenefit" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_FederalIncomeTaxExpenseBenefitContinuingOperations" xlink:type="locator" xlink:label="us-gaap_FederalIncomeTaxExpenseBenefitContinuingOperations" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_DeferredFederalIncomeTaxExpenseBenefit" xlink:type="locator" xlink:label="us-gaap_DeferredFederalIncomeTaxExpenseBenefit" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_CurrentFederalTaxExpenseBenefit" xlink:type="locator" xlink:label="us-gaap_CurrentFederalTaxExpenseBenefit" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_PredecessorMember" xlink:type="locator" xlink:label="us-gaap_PredecessorMember" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ScenarioUnspecifiedDomain" xlink:type="locator" xlink:label="us-gaap_ScenarioUnspecifiedDomain" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_StatementScenarioAxis" xlink:type="locator" xlink:label="us-gaap_StatementScenarioAxis" />
    <loc xlink:href="medp-20161231.xsd#medp_IncomeTaxDisclosureTable" xlink:type="locator" xlink:label="medp_IncomeTaxDisclosureTable" />
    <loc xlink:href="medp-20161231.xsd#medp_IncomeTaxDisclosureLineItems" xlink:type="locator" xlink:label="medp_IncomeTaxDisclosureLineItems" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="medp_IncomeTaxDisclosureLineItems" xlink:to="medp_IncomeTaxDisclosureTable" order="10090.00" priority="2" use="optional" xbrldt:contextElement="segment" xbrldt:closed="true" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="medp_IncomeTaxDisclosureTable" xlink:to="us-gaap_StatementScenarioAxis" order="10120.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_StatementScenarioAxis" xlink:to="us-gaap_ScenarioUnspecifiedDomain" order="10140.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ScenarioUnspecifiedDomain" xlink:to="us-gaap_PredecessorMember" order="10160.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="medp_IncomeTaxDisclosureLineItems" xlink:to="us-gaap_CurrentFederalTaxExpenseBenefit" order="10340.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="medp_IncomeTaxDisclosureLineItems" xlink:to="us-gaap_DeferredFederalIncomeTaxExpenseBenefit" order="10500.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="medp_IncomeTaxDisclosureLineItems" xlink:to="us-gaap_FederalIncomeTaxExpenseBenefitContinuingOperations" order="10660.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="medp_IncomeTaxDisclosureLineItems" xlink:to="us-gaap_CurrentStateAndLocalTaxExpenseBenefit" order="10850.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="medp_IncomeTaxDisclosureLineItems" xlink:to="us-gaap_DeferredStateAndLocalIncomeTaxExpenseBenefit" order="11010.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="medp_IncomeTaxDisclosureLineItems" xlink:to="us-gaap_StateAndLocalIncomeTaxExpenseBenefitContinuingOperations" order="11170.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="medp_IncomeTaxDisclosureLineItems" xlink:to="us-gaap_CurrentForeignTaxExpenseBenefit" order="11360.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="medp_IncomeTaxDisclosureLineItems" xlink:to="us-gaap_DeferredForeignIncomeTaxExpenseBenefit" order="11520.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="medp_IncomeTaxDisclosureLineItems" xlink:to="us-gaap_ForeignIncomeTaxExpenseBenefitContinuingOperations" order="11680.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="medp_IncomeTaxDisclosureLineItems" xlink:to="us-gaap_CurrentIncomeTaxExpenseBenefit" order="11870.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="medp_IncomeTaxDisclosureLineItems" xlink:to="us-gaap_DeferredIncomeTaxesAndTaxCredits" order="12030.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="medp_IncomeTaxDisclosureLineItems" xlink:to="us-gaap_IncomeTaxExpenseBenefit" order="12190.00" priority="2" use="optional" />
  </definitionLink>
  <roleRef roleURI="http://www.medpace.com/20161231/taxonomy/role/DisclosureIncomeTaxesSummaryOfDifferenceBetweenStatutoryRateForFederalIncomeTaxAndEffectiveIncomeTaxRateDetails" xlink:href="medp-20161231.xsd#Role_DisclosureIncomeTaxesSummaryOfDifferenceBetweenStatutoryRateForFederalIncomeTaxAndEffectiveIncomeTaxRateDetails" xlink:type="simple" />
  <definitionLink xlink:type="extended" xlink:role="http://www.medpace.com/20161231/taxonomy/role/DisclosureIncomeTaxesSummaryOfDifferenceBetweenStatutoryRateForFederalIncomeTaxAndEffectiveIncomeTaxRateDetails">
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_EffectiveIncomeTaxRateContinuingOperations" xlink:type="locator" xlink:label="us-gaap_EffectiveIncomeTaxRateContinuingOperations" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_EffectiveIncomeTaxRateReconciliationOtherReconcilingItemsPercent" xlink:type="locator" xlink:label="us-gaap_EffectiveIncomeTaxRateReconciliationOtherReconcilingItemsPercent" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_EffectiveIncomeTaxRateReconciliationTaxContingencies" xlink:type="locator" xlink:label="us-gaap_EffectiveIncomeTaxRateReconciliationTaxContingencies" />
    <loc xlink:href="medp-20161231.xsd#medp_EffectiveIncomeTaxReconciliationStateAndLocalTaxCreditsAndAdjustments" xlink:type="locator" xlink:label="medp_EffectiveIncomeTaxReconciliationStateAndLocalTaxCreditsAndAdjustments" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_EffectiveIncomeTaxRateReconciliationNondeductibleExpenseOther" xlink:type="locator" xlink:label="us-gaap_EffectiveIncomeTaxRateReconciliationNondeductibleExpenseOther" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_EffectiveIncomeTaxRateReconciliationNondeductibleExpenseShareBasedCompensationCost" xlink:type="locator" xlink:label="us-gaap_EffectiveIncomeTaxRateReconciliationNondeductibleExpenseShareBasedCompensationCost" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_EffectiveIncomeTaxRateReconciliationNondeductibleExpenseImpairmentLosses" xlink:type="locator" xlink:label="us-gaap_EffectiveIncomeTaxRateReconciliationNondeductibleExpenseImpairmentLosses" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_EffectiveIncomeTaxRateReconciliationChangeInDeferredTaxAssetsValuationAllowance" xlink:type="locator" xlink:label="us-gaap_EffectiveIncomeTaxRateReconciliationChangeInDeferredTaxAssetsValuationAllowance" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_EffectiveIncomeTaxRateReconciliationForeignIncomeTaxRateDifferential" xlink:type="locator" xlink:label="us-gaap_EffectiveIncomeTaxRateReconciliationForeignIncomeTaxRateDifferential" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_EffectiveIncomeTaxRateReconciliationStateAndLocalIncomeTaxes" xlink:type="locator" xlink:label="us-gaap_EffectiveIncomeTaxRateReconciliationStateAndLocalIncomeTaxes" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_EffectiveIncomeTaxRateReconciliationAtFederalStatutoryIncomeTaxRate" xlink:type="locator" xlink:label="us-gaap_EffectiveIncomeTaxRateReconciliationAtFederalStatutoryIncomeTaxRate" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_IncomeTaxExpenseBenefit" xlink:type="locator" xlink:label="us-gaap_IncomeTaxExpenseBenefit" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_IncomeTaxReconciliationOtherReconcilingItems" xlink:type="locator" xlink:label="us-gaap_IncomeTaxReconciliationOtherReconcilingItems" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_IncomeTaxReconciliationTaxContingencies" xlink:type="locator" xlink:label="us-gaap_IncomeTaxReconciliationTaxContingencies" />
    <loc xlink:href="medp-20161231.xsd#medp_IncomeTaxReconciliationStateAndLocalTaxCredits" xlink:type="locator" xlink:label="medp_IncomeTaxReconciliationStateAndLocalTaxCredits" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_IncomeTaxReconciliationNondeductibleExpenseOther" xlink:type="locator" xlink:label="us-gaap_IncomeTaxReconciliationNondeductibleExpenseOther" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_IncomeTaxReconciliationNondeductibleExpenseShareBasedCompensationCost" xlink:type="locator" xlink:label="us-gaap_IncomeTaxReconciliationNondeductibleExpenseShareBasedCompensationCost" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_IncomeTaxReconciliationNondeductibleExpenseImpairmentLosses" xlink:type="locator" xlink:label="us-gaap_IncomeTaxReconciliationNondeductibleExpenseImpairmentLosses" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_IncomeTaxReconciliationChangeInDeferredTaxAssetsValuationAllowance" xlink:type="locator" xlink:label="us-gaap_IncomeTaxReconciliationChangeInDeferredTaxAssetsValuationAllowance" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_IncomeTaxReconciliationForeignIncomeTaxRateDifferential" xlink:type="locator" xlink:label="us-gaap_IncomeTaxReconciliationForeignIncomeTaxRateDifferential" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_IncomeTaxReconciliationStateAndLocalIncomeTaxes" xlink:type="locator" xlink:label="us-gaap_IncomeTaxReconciliationStateAndLocalIncomeTaxes" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_IncomeTaxReconciliationIncomeTaxExpenseBenefitAtFederalStatutoryIncomeTaxRate" xlink:type="locator" xlink:label="us-gaap_IncomeTaxReconciliationIncomeTaxExpenseBenefitAtFederalStatutoryIncomeTaxRate" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_PredecessorMember" xlink:type="locator" xlink:label="us-gaap_PredecessorMember" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ScenarioUnspecifiedDomain" xlink:type="locator" xlink:label="us-gaap_ScenarioUnspecifiedDomain" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_StatementScenarioAxis" xlink:type="locator" xlink:label="us-gaap_StatementScenarioAxis" />
    <loc xlink:href="medp-20161231.xsd#medp_ScheduleOfUnrecognizedTaxBenefitsTable" xlink:type="locator" xlink:label="medp_ScheduleOfUnrecognizedTaxBenefitsTable" />
    <loc xlink:href="medp-20161231.xsd#medp_IncomeTaxDisclosureLineItems" xlink:type="locator" xlink:label="medp_IncomeTaxDisclosureLineItems" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="medp_IncomeTaxDisclosureLineItems" xlink:to="medp_ScheduleOfUnrecognizedTaxBenefitsTable" order="10210.00" priority="2" use="optional" xbrldt:contextElement="segment" xbrldt:closed="true" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="medp_ScheduleOfUnrecognizedTaxBenefitsTable" xlink:to="us-gaap_StatementScenarioAxis" order="10240.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_StatementScenarioAxis" xlink:to="us-gaap_ScenarioUnspecifiedDomain" order="10260.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ScenarioUnspecifiedDomain" xlink:to="us-gaap_PredecessorMember" order="10280.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="medp_IncomeTaxDisclosureLineItems" xlink:to="us-gaap_IncomeTaxReconciliationIncomeTaxExpenseBenefitAtFederalStatutoryIncomeTaxRate" order="10360.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="medp_IncomeTaxDisclosureLineItems" xlink:to="us-gaap_IncomeTaxReconciliationStateAndLocalIncomeTaxes" order="10520.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="medp_IncomeTaxDisclosureLineItems" xlink:to="us-gaap_IncomeTaxReconciliationForeignIncomeTaxRateDifferential" order="10680.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="medp_IncomeTaxDisclosureLineItems" xlink:to="us-gaap_IncomeTaxReconciliationChangeInDeferredTaxAssetsValuationAllowance" order="10840.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="medp_IncomeTaxDisclosureLineItems" xlink:to="us-gaap_IncomeTaxReconciliationNondeductibleExpenseImpairmentLosses" order="11000.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="medp_IncomeTaxDisclosureLineItems" xlink:to="us-gaap_IncomeTaxReconciliationNondeductibleExpenseShareBasedCompensationCost" order="11160.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="medp_IncomeTaxDisclosureLineItems" xlink:to="us-gaap_IncomeTaxReconciliationNondeductibleExpenseOther" order="11320.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="medp_IncomeTaxDisclosureLineItems" xlink:to="medp_IncomeTaxReconciliationStateAndLocalTaxCredits" order="11480.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="medp_IncomeTaxDisclosureLineItems" xlink:to="us-gaap_IncomeTaxReconciliationTaxContingencies" order="11640.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="medp_IncomeTaxDisclosureLineItems" xlink:to="us-gaap_IncomeTaxReconciliationOtherReconcilingItems" order="11800.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="medp_IncomeTaxDisclosureLineItems" xlink:to="us-gaap_IncomeTaxExpenseBenefit" order="11960.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="medp_IncomeTaxDisclosureLineItems" xlink:to="us-gaap_EffectiveIncomeTaxRateReconciliationAtFederalStatutoryIncomeTaxRate" order="12070.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="medp_IncomeTaxDisclosureLineItems" xlink:to="us-gaap_EffectiveIncomeTaxRateReconciliationStateAndLocalIncomeTaxes" order="12230.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="medp_IncomeTaxDisclosureLineItems" xlink:to="us-gaap_EffectiveIncomeTaxRateReconciliationForeignIncomeTaxRateDifferential" order="12390.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="medp_IncomeTaxDisclosureLineItems" xlink:to="us-gaap_EffectiveIncomeTaxRateReconciliationChangeInDeferredTaxAssetsValuationAllowance" order="12550.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="medp_IncomeTaxDisclosureLineItems" xlink:to="us-gaap_EffectiveIncomeTaxRateReconciliationNondeductibleExpenseImpairmentLosses" order="12710.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="medp_IncomeTaxDisclosureLineItems" xlink:to="us-gaap_EffectiveIncomeTaxRateReconciliationNondeductibleExpenseShareBasedCompensationCost" order="12870.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="medp_IncomeTaxDisclosureLineItems" xlink:to="us-gaap_EffectiveIncomeTaxRateReconciliationNondeductibleExpenseOther" order="13030.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="medp_IncomeTaxDisclosureLineItems" xlink:to="medp_EffectiveIncomeTaxReconciliationStateAndLocalTaxCreditsAndAdjustments" order="13190.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="medp_IncomeTaxDisclosureLineItems" xlink:to="us-gaap_EffectiveIncomeTaxRateReconciliationTaxContingencies" order="13350.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="medp_IncomeTaxDisclosureLineItems" xlink:to="us-gaap_EffectiveIncomeTaxRateReconciliationOtherReconcilingItemsPercent" order="13510.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="medp_IncomeTaxDisclosureLineItems" xlink:to="us-gaap_EffectiveIncomeTaxRateContinuingOperations" order="13670.00" priority="2" use="optional" />
  </definitionLink>
  <roleRef roleURI="http://www.medpace.com/20161231/taxonomy/role/DisclosureIncomeTaxesAdditionalInformationDetails" xlink:href="medp-20161231.xsd#Role_DisclosureIncomeTaxesAdditionalInformationDetails" xlink:type="simple" />
  <definitionLink xlink:type="extended" xlink:role="http://www.medpace.com/20161231/taxonomy/role/DisclosureIncomeTaxesAdditionalInformationDetails">
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_OpenTaxYear" xlink:type="locator" xlink:label="us-gaap_OpenTaxYear" />
    <loc xlink:href="medp-20161231.xsd#medp_NumberOfTaxPeriodsSubjectToAudit" xlink:type="locator" xlink:label="medp_NumberOfTaxPeriodsSubjectToAudit" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_LiabilityForUncertainTaxPositionsNoncurrent" xlink:type="locator" xlink:label="us-gaap_LiabilityForUncertainTaxPositionsNoncurrent" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_IncomeTaxExaminationPenaltiesAndInterestAccrued" xlink:type="locator" xlink:label="us-gaap_IncomeTaxExaminationPenaltiesAndInterestAccrued" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_DeferredTaxAssetsGross" xlink:type="locator" xlink:label="us-gaap_DeferredTaxAssetsGross" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_DeferredTaxAssetsTaxDeferredExpenseReservesAndAccrualsImpairmentLosses" xlink:type="locator" xlink:label="us-gaap_DeferredTaxAssetsTaxDeferredExpenseReservesAndAccrualsImpairmentLosses" />
    <loc xlink:href="medp-20161231.xsd#medp_NetOperatingLossCarryforwardsForeignExpirationYear" xlink:type="locator" xlink:label="medp_NetOperatingLossCarryforwardsForeignExpirationYear" />
    <loc xlink:href="medp-20161231.xsd#medp_PercentageOfNetOperatingLossCarryforwardsForeign" xlink:type="locator" xlink:label="medp_PercentageOfNetOperatingLossCarryforwardsForeign" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_DeferredTaxAssetsValuationAllowance" xlink:type="locator" xlink:label="us-gaap_DeferredTaxAssetsValuationAllowance" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_DeferredTaxAssetsOperatingLossCarryforwardsForeign" xlink:type="locator" xlink:label="us-gaap_DeferredTaxAssetsOperatingLossCarryforwardsForeign" />
    <loc xlink:href="medp-20161231.xsd#medp_DeferredTaxAssetsOperatingLossCarryforwardsExpirationYear" xlink:type="locator" xlink:label="medp_DeferredTaxAssetsOperatingLossCarryforwardsExpirationYear" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_DeferredTaxAssetsOperatingLossCarryforwardsSubjectToExpiration" xlink:type="locator" xlink:label="us-gaap_DeferredTaxAssetsOperatingLossCarryforwardsSubjectToExpiration" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_UndistributedEarningsOfForeignSubsidiaries" xlink:type="locator" xlink:label="us-gaap_UndistributedEarningsOfForeignSubsidiaries" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_LatestTaxYearMember" xlink:type="locator" xlink:label="us-gaap_LatestTaxYearMember" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_TaxYear2012Member" xlink:type="locator" xlink:label="us-gaap_TaxYear2012Member" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_TaxPeriodDomain" xlink:type="locator" xlink:label="us-gaap_TaxPeriodDomain_2" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_TaxPeriodDomain" xlink:type="locator" xlink:label="us-gaap_TaxPeriodDomain" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_TaxPeriodAxis" xlink:type="locator" xlink:label="us-gaap_TaxPeriodAxis" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ForeignCountryMember" xlink:type="locator" xlink:label="us-gaap_ForeignCountryMember" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_MinimumMember" xlink:type="locator" xlink:label="us-gaap_MinimumMember" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_MaximumMember" xlink:type="locator" xlink:label="us-gaap_MaximumMember" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_RangeMember" xlink:type="locator" xlink:label="us-gaap_RangeMember" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_RangeAxis" xlink:type="locator" xlink:label="us-gaap_RangeAxis" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_StateAndLocalJurisdictionMember" xlink:type="locator" xlink:label="us-gaap_StateAndLocalJurisdictionMember" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_IncomeTaxAuthorityDomain" xlink:type="locator" xlink:label="us-gaap_IncomeTaxAuthorityDomain_2" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_IncomeTaxAuthorityDomain" xlink:type="locator" xlink:label="us-gaap_IncomeTaxAuthorityDomain" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_IncomeTaxAuthorityAxis" xlink:type="locator" xlink:label="us-gaap_IncomeTaxAuthorityAxis" />
    <loc xlink:href="medp-20161231.xsd#medp_IncomeTaxDisclosureTable" xlink:type="locator" xlink:label="medp_IncomeTaxDisclosureTable" />
    <loc xlink:href="medp-20161231.xsd#medp_IncomeTaxDisclosureLineItems" xlink:type="locator" xlink:label="medp_IncomeTaxDisclosureLineItems" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="medp_IncomeTaxDisclosureLineItems" xlink:to="medp_IncomeTaxDisclosureTable" order="10010.00" priority="2" use="optional" xbrldt:contextElement="segment" xbrldt:closed="true" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="medp_IncomeTaxDisclosureTable" xlink:to="us-gaap_IncomeTaxAuthorityAxis" order="10040.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="us-gaap_IncomeTaxAuthorityAxis" xlink:to="us-gaap_IncomeTaxAuthorityDomain_2" order="10060.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_IncomeTaxAuthorityAxis" xlink:to="us-gaap_IncomeTaxAuthorityDomain" order="10060.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_IncomeTaxAuthorityDomain" xlink:to="us-gaap_StateAndLocalJurisdictionMember" order="10080.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="medp_IncomeTaxDisclosureTable" xlink:to="us-gaap_RangeAxis" order="10110.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_RangeAxis" xlink:to="us-gaap_RangeMember" order="10130.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_RangeMember" xlink:to="us-gaap_MaximumMember" order="10150.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_RangeMember" xlink:to="us-gaap_MinimumMember" order="10200.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_IncomeTaxAuthorityDomain" xlink:to="us-gaap_ForeignCountryMember" order="10270.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="medp_IncomeTaxDisclosureTable" xlink:to="us-gaap_TaxPeriodAxis" order="10280.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="us-gaap_TaxPeriodAxis" xlink:to="us-gaap_TaxPeriodDomain_2" order="10300.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_TaxPeriodAxis" xlink:to="us-gaap_TaxPeriodDomain" order="10300.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_TaxPeriodDomain" xlink:to="us-gaap_TaxYear2012Member" order="10320.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_TaxPeriodDomain" xlink:to="us-gaap_LatestTaxYearMember" order="10340.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="medp_IncomeTaxDisclosureLineItems" xlink:to="us-gaap_UndistributedEarningsOfForeignSubsidiaries" order="10370.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="medp_IncomeTaxDisclosureLineItems" xlink:to="us-gaap_DeferredTaxAssetsOperatingLossCarryforwardsSubjectToExpiration" order="10460.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="medp_IncomeTaxDisclosureLineItems" xlink:to="medp_DeferredTaxAssetsOperatingLossCarryforwardsExpirationYear" order="10520.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="medp_IncomeTaxDisclosureLineItems" xlink:to="us-gaap_DeferredTaxAssetsOperatingLossCarryforwardsForeign" order="10610.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="medp_IncomeTaxDisclosureLineItems" xlink:to="us-gaap_DeferredTaxAssetsValuationAllowance" order="10650.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="medp_IncomeTaxDisclosureLineItems" xlink:to="medp_PercentageOfNetOperatingLossCarryforwardsForeign" order="10710.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="medp_IncomeTaxDisclosureLineItems" xlink:to="medp_NetOperatingLossCarryforwardsForeignExpirationYear" order="10770.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="medp_IncomeTaxDisclosureLineItems" xlink:to="us-gaap_DeferredTaxAssetsTaxDeferredExpenseReservesAndAccrualsImpairmentLosses" order="10920.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="medp_IncomeTaxDisclosureLineItems" xlink:to="us-gaap_DeferredTaxAssetsGross" order="10980.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="medp_IncomeTaxDisclosureLineItems" xlink:to="us-gaap_IncomeTaxExaminationPenaltiesAndInterestAccrued" order="11130.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="medp_IncomeTaxDisclosureLineItems" xlink:to="us-gaap_LiabilityForUncertainTaxPositionsNoncurrent" order="11210.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="medp_IncomeTaxDisclosureLineItems" xlink:to="medp_NumberOfTaxPeriodsSubjectToAudit" order="11320.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="medp_IncomeTaxDisclosureLineItems" xlink:to="us-gaap_OpenTaxYear" order="11460.00" priority="2" use="optional" />
  </definitionLink>
  <roleRef roleURI="http://www.medpace.com/20161231/taxonomy/role/DisclosureIncomeTaxesScheduleOfAnnualActivityRelatedToValuationAllowanceDetails" xlink:href="medp-20161231.xsd#Role_DisclosureIncomeTaxesScheduleOfAnnualActivityRelatedToValuationAllowanceDetails" xlink:type="simple" />
  <definitionLink xlink:type="extended" xlink:role="http://www.medpace.com/20161231/taxonomy/role/DisclosureIncomeTaxesScheduleOfAnnualActivityRelatedToValuationAllowanceDetails">
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ValuationAllowancesAndReservesDeductions" xlink:type="locator" xlink:label="us-gaap_ValuationAllowancesAndReservesDeductions" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ValuationAllowancesAndReservesChargedToCostAndExpense" xlink:type="locator" xlink:label="us-gaap_ValuationAllowancesAndReservesChargedToCostAndExpense" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ValuationAllowancesAndReservesBalance" xlink:type="locator" xlink:label="us-gaap_ValuationAllowancesAndReservesBalance" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_PredecessorMember" xlink:type="locator" xlink:label="us-gaap_PredecessorMember" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ScenarioUnspecifiedDomain" xlink:type="locator" xlink:label="us-gaap_ScenarioUnspecifiedDomain" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_StatementScenarioAxis" xlink:type="locator" xlink:label="us-gaap_StatementScenarioAxis" />
    <loc xlink:href="medp-20161231.xsd#medp_ScheduleOfUnrecognizedTaxBenefitsTable" xlink:type="locator" xlink:label="medp_ScheduleOfUnrecognizedTaxBenefitsTable" />
    <loc xlink:href="medp-20161231.xsd#medp_IncomeTaxDisclosureLineItems" xlink:type="locator" xlink:label="medp_IncomeTaxDisclosureLineItems" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="medp_IncomeTaxDisclosureLineItems" xlink:to="medp_ScheduleOfUnrecognizedTaxBenefitsTable" order="10010.00" priority="2" use="optional" xbrldt:contextElement="segment" xbrldt:closed="true" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="medp_ScheduleOfUnrecognizedTaxBenefitsTable" xlink:to="us-gaap_StatementScenarioAxis" order="10040.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_StatementScenarioAxis" xlink:to="us-gaap_ScenarioUnspecifiedDomain" order="10060.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ScenarioUnspecifiedDomain" xlink:to="us-gaap_PredecessorMember" order="10080.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="medp_IncomeTaxDisclosureLineItems" xlink:to="us-gaap_ValuationAllowancesAndReservesBalance" order="10110.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="medp_IncomeTaxDisclosureLineItems" xlink:to="us-gaap_ValuationAllowancesAndReservesChargedToCostAndExpense" order="10270.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="medp_IncomeTaxDisclosureLineItems" xlink:to="us-gaap_ValuationAllowancesAndReservesDeductions" order="10430.00" priority="2" use="optional" />
  </definitionLink>
  <roleRef roleURI="http://www.medpace.com/20161231/taxonomy/role/DisclosureIncomeTaxesScheduleOfGrossUnrecognizedTaxBenefitsDetails" xlink:href="medp-20161231.xsd#Role_DisclosureIncomeTaxesScheduleOfGrossUnrecognizedTaxBenefitsDetails" xlink:type="simple" />
  <definitionLink xlink:type="extended" xlink:role="http://www.medpace.com/20161231/taxonomy/role/DisclosureIncomeTaxesScheduleOfGrossUnrecognizedTaxBenefitsDetails">
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_UnrecognizedTaxBenefitsReductionsResultingFromLapseOfApplicableStatuteOfLimitations" xlink:type="locator" xlink:label="us-gaap_UnrecognizedTaxBenefitsReductionsResultingFromLapseOfApplicableStatuteOfLimitations" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_UnrecognizedTaxBenefitsIncreasesResultingFromCurrentPeriodTaxPositions" xlink:type="locator" xlink:label="us-gaap_UnrecognizedTaxBenefitsIncreasesResultingFromCurrentPeriodTaxPositions" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_UnrecognizedTaxBenefitsDecreasesResultingFromPriorPeriodTaxPositions" xlink:type="locator" xlink:label="us-gaap_UnrecognizedTaxBenefitsDecreasesResultingFromPriorPeriodTaxPositions" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_UnrecognizedTaxBenefitsIncreasesResultingFromPriorPeriodTaxPositions" xlink:type="locator" xlink:label="us-gaap_UnrecognizedTaxBenefitsIncreasesResultingFromPriorPeriodTaxPositions" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_UnrecognizedTaxBenefits" xlink:type="locator" xlink:label="us-gaap_UnrecognizedTaxBenefits" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_PredecessorMember" xlink:type="locator" xlink:label="us-gaap_PredecessorMember" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ScenarioUnspecifiedDomain" xlink:type="locator" xlink:label="us-gaap_ScenarioUnspecifiedDomain" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_StatementScenarioAxis" xlink:type="locator" xlink:label="us-gaap_StatementScenarioAxis" />
    <loc xlink:href="medp-20161231.xsd#medp_ScheduleOfUnrecognizedTaxBenefitsTable" xlink:type="locator" xlink:label="medp_ScheduleOfUnrecognizedTaxBenefitsTable" />
    <loc xlink:href="medp-20161231.xsd#medp_IncomeTaxDisclosureLineItems" xlink:type="locator" xlink:label="medp_IncomeTaxDisclosureLineItems" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="medp_IncomeTaxDisclosureLineItems" xlink:to="medp_ScheduleOfUnrecognizedTaxBenefitsTable" order="10010.00" priority="2" use="optional" xbrldt:contextElement="segment" xbrldt:closed="true" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="medp_ScheduleOfUnrecognizedTaxBenefitsTable" xlink:to="us-gaap_StatementScenarioAxis" order="10040.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_StatementScenarioAxis" xlink:to="us-gaap_ScenarioUnspecifiedDomain" order="10060.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ScenarioUnspecifiedDomain" xlink:to="us-gaap_PredecessorMember" order="10080.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="medp_IncomeTaxDisclosureLineItems" xlink:to="us-gaap_UnrecognizedTaxBenefits" order="10110.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="medp_IncomeTaxDisclosureLineItems" xlink:to="us-gaap_UnrecognizedTaxBenefitsIncreasesResultingFromPriorPeriodTaxPositions" order="10270.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="medp_IncomeTaxDisclosureLineItems" xlink:to="us-gaap_UnrecognizedTaxBenefitsDecreasesResultingFromPriorPeriodTaxPositions" order="10430.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="medp_IncomeTaxDisclosureLineItems" xlink:to="us-gaap_UnrecognizedTaxBenefitsIncreasesResultingFromCurrentPeriodTaxPositions" order="10590.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="medp_IncomeTaxDisclosureLineItems" xlink:to="us-gaap_UnrecognizedTaxBenefitsReductionsResultingFromLapseOfApplicableStatuteOfLimitations" order="10750.00" priority="2" use="optional" />
  </definitionLink>
  <roleRef roleURI="http://www.medpace.com/20161231/taxonomy/role/DisclosureMiscellaneousExpenseIncomeNetComponentsOfMiscellaneousExpenseIncomeNetDetails" xlink:href="medp-20161231.xsd#Role_DisclosureMiscellaneousExpenseIncomeNetComponentsOfMiscellaneousExpenseIncomeNetDetails" xlink:type="simple" />
  <definitionLink xlink:type="extended" xlink:role="http://www.medpace.com/20161231/taxonomy/role/DisclosureMiscellaneousExpenseIncomeNetComponentsOfMiscellaneousExpenseIncomeNetDetails">
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_OtherNonoperatingIncomeExpense" xlink:type="locator" xlink:label="us-gaap_OtherNonoperatingIncomeExpense" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_OtherIncome" xlink:type="locator" xlink:label="us-gaap_OtherIncome" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ForeignCurrencyTransactionGainLossRealized" xlink:type="locator" xlink:label="us-gaap_ForeignCurrencyTransactionGainLossRealized" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_PredecessorMember" xlink:type="locator" xlink:label="us-gaap_PredecessorMember" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ScenarioUnspecifiedDomain" xlink:type="locator" xlink:label="us-gaap_ScenarioUnspecifiedDomain" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_StatementScenarioAxis" xlink:type="locator" xlink:label="us-gaap_StatementScenarioAxis" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_StatementTable" xlink:type="locator" xlink:label="us-gaap_StatementTable" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_StatementLineItems" xlink:type="locator" xlink:label="us-gaap_StatementLineItems" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="us-gaap_StatementLineItems" xlink:to="us-gaap_StatementTable" order="10030.00" priority="2" use="optional" xbrldt:contextElement="segment" xbrldt:closed="true" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="us-gaap_StatementTable" xlink:to="us-gaap_StatementScenarioAxis" order="10060.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_StatementScenarioAxis" xlink:to="us-gaap_ScenarioUnspecifiedDomain" order="10080.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ScenarioUnspecifiedDomain" xlink:to="us-gaap_PredecessorMember" order="10100.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_StatementLineItems" xlink:to="us-gaap_ForeignCurrencyTransactionGainLossRealized" order="10130.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_StatementLineItems" xlink:to="us-gaap_OtherIncome" order="10290.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_StatementLineItems" xlink:to="us-gaap_OtherNonoperatingIncomeExpense" order="10450.00" priority="2" use="optional" />
  </definitionLink>
  <roleRef roleURI="http://www.medpace.com/20161231/taxonomy/role/DisclosureRelatedPartyTransactionsAdditionalInformationDetails" xlink:href="medp-20161231.xsd#Role_DisclosureRelatedPartyTransactionsAdditionalInformationDetails" xlink:type="simple" />
  <definitionLink xlink:type="extended" xlink:role="http://www.medpace.com/20161231/taxonomy/role/DisclosureRelatedPartyTransactionsAdditionalInformationDetails">
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_DueToRelatedPartiesNoncurrent" xlink:type="locator" xlink:label="us-gaap_DueToRelatedPartiesNoncurrent" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_DueToRelatedPartiesCurrent" xlink:type="locator" xlink:label="us-gaap_DueToRelatedPartiesCurrent" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_DueFromRelatedPartiesNoncurrent" xlink:type="locator" xlink:label="us-gaap_DueFromRelatedPartiesNoncurrent" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_DueFromRelatedPartiesCurrent" xlink:type="locator" xlink:label="us-gaap_DueFromRelatedPartiesCurrent" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_AllocatedShareBasedCompensationExpense" xlink:type="locator" xlink:label="us-gaap_AllocatedShareBasedCompensationExpense" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_StockIssuedDuringPeriodSharesEmployeeStockOwnershipPlan" xlink:type="locator" xlink:label="us-gaap_StockIssuedDuringPeriodSharesEmployeeStockOwnershipPlan" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_CapitalLeasesBalanceSheetAssetsByMajorClassNet" xlink:type="locator" xlink:label="us-gaap_CapitalLeasesBalanceSheetAssetsByMajorClassNet" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_CapitalLeaseObligationsNoncurrent" xlink:type="locator" xlink:label="us-gaap_CapitalLeaseObligationsNoncurrent" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_CapitalLeaseObligationsCurrent" xlink:type="locator" xlink:label="us-gaap_CapitalLeaseObligationsCurrent" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_AccretionExpense" xlink:type="locator" xlink:label="us-gaap_AccretionExpense" />
    <loc xlink:href="medp-20161231.xsd#medp_LeaseExpirationYear" xlink:type="locator" xlink:label="medp_LeaseExpirationYear" />
    <loc xlink:href="medp-20161231.xsd#medp_LeaseOccupancyYear" xlink:type="locator" xlink:label="medp_LeaseOccupancyYear" />
    <loc xlink:href="medp-20161231.xsd#medp_NumberOfBuilding" xlink:type="locator" xlink:label="medp_NumberOfBuilding" />
    <loc xlink:href="medp-20161231.xsd#medp_NumberOfLeaseAgreements" xlink:type="locator" xlink:label="medp_NumberOfLeaseAgreements" />
    <loc xlink:href="medp-20161231.xsd#medp_OperatingLeasesLeaseBasis" xlink:type="locator" xlink:label="medp_OperatingLeasesLeaseBasis" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_OperatingLeasesRentExpenseNet" xlink:type="locator" xlink:label="us-gaap_OperatingLeasesRentExpenseNet" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_LeaseAndRentalExpense" xlink:type="locator" xlink:label="us-gaap_LeaseAndRentalExpense" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_LesseeLeasingArrangementsOperatingLeasesRenewalTerm" xlink:type="locator" xlink:label="us-gaap_LesseeLeasingArrangementsOperatingLeasesRenewalTerm" />
    <loc xlink:href="medp-20161231.xsd#medp_NumberOfLeaseRenewalOptions" xlink:type="locator" xlink:label="medp_NumberOfLeaseRenewalOptions" />
    <loc xlink:href="medp-20161231.xsd#medp_LeaseExpirationMonthAndYear" xlink:type="locator" xlink:label="medp_LeaseExpirationMonthAndYear" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_LesseeLeasingArrangementsOperatingLeasesTermOfContract" xlink:type="locator" xlink:label="us-gaap_LesseeLeasingArrangementsOperatingLeasesTermOfContract" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_RelatedPartyTaxExpenseDueToAffiliatesCurrent" xlink:type="locator" xlink:label="us-gaap_RelatedPartyTaxExpenseDueToAffiliatesCurrent" />
    <loc xlink:href="medp-20161231.xsd#medp_PreFundedStudyCostsWithRelatedParties" xlink:type="locator" xlink:label="medp_PreFundedStudyCostsWithRelatedParties" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_DeferredRevenueCurrent" xlink:type="locator" xlink:label="us-gaap_DeferredRevenueCurrent" />
    <loc xlink:href="medp-20161231.xsd#medp_UnbilledContractReceivablesCurrentWithRelatedParties" xlink:type="locator" xlink:label="medp_UnbilledContractReceivablesCurrentWithRelatedParties" />
    <loc xlink:href="medp-20161231.xsd#medp_ReimbursedOutOfPocketExpensesWithRelatedParties" xlink:type="locator" xlink:label="medp_ReimbursedOutOfPocketExpensesWithRelatedParties" />
    <loc xlink:href="medp-20161231.xsd#medp_ReimbursedOutOfPocketRevenueWithRelatedParties" xlink:type="locator" xlink:label="medp_ReimbursedOutOfPocketRevenueWithRelatedParties" />
    <loc xlink:href="medp-20161231.xsd#medp_CommissionsRelatedParty" xlink:type="locator" xlink:label="medp_CommissionsRelatedParty" />
    <loc xlink:href="medp-20161231.xsd#medp_ClinicalTrialServicesAgreementNoticePeriodPriorToCancellation" xlink:type="locator" xlink:label="medp_ClinicalTrialServicesAgreementNoticePeriodPriorToCancellation" />
    <loc xlink:href="medp-20161231.xsd#medp_PercentageOfSalesCommission" xlink:type="locator" xlink:label="medp_PercentageOfSalesCommission" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_Investments" xlink:type="locator" xlink:label="us-gaap_Investments" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_AccountsReceivableRelatedPartiesCurrent" xlink:type="locator" xlink:label="us-gaap_AccountsReceivableRelatedPartiesCurrent" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_RevenueFromRelatedParties" xlink:type="locator" xlink:label="us-gaap_RevenueFromRelatedParties" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_RelatedPartyTransactionExpensesFromTransactionsWithRelatedParty" xlink:type="locator" xlink:label="us-gaap_RelatedPartyTransactionExpensesFromTransactionsWithRelatedParty" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_NoninterestExpenseDirectorsFees" xlink:type="locator" xlink:label="us-gaap_NoninterestExpenseDirectorsFees" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_AccountsPayableRelatedPartiesCurrent" xlink:type="locator" xlink:label="us-gaap_AccountsPayableRelatedPartiesCurrent" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_TravelAndEntertainmentExpense" xlink:type="locator" xlink:label="us-gaap_TravelAndEntertainmentExpense" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ManagementFeeExpense" xlink:type="locator" xlink:label="us-gaap_ManagementFeeExpense" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_DueFromEmployeesNoncurrent" xlink:type="locator" xlink:label="us-gaap_DueFromEmployeesNoncurrent" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_DueFromEmployeesCurrent" xlink:type="locator" xlink:label="us-gaap_DueFromEmployeesCurrent" />
    <loc xlink:href="medp-20161231.xsd#medp_OtherTaxingAuthoritiesMember" xlink:type="locator" xlink:label="medp_OtherTaxingAuthoritiesMember" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_StateAndLocalJurisdictionMember" xlink:type="locator" xlink:label="us-gaap_StateAndLocalJurisdictionMember" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_IncomeTaxAuthorityDomain" xlink:type="locator" xlink:label="us-gaap_IncomeTaxAuthorityDomain" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_IncomeTaxAuthorityAxis" xlink:type="locator" xlink:label="us-gaap_IncomeTaxAuthorityAxis" />
    <loc xlink:href="medp-20161231.xsd#medp_FormerOwnerMember" xlink:type="locator" xlink:label="medp_FormerOwnerMember" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_OtherNoncurrentLiabilitiesMember" xlink:type="locator" xlink:label="us-gaap_OtherNoncurrentLiabilitiesMember" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_OtherCurrentLiabilitiesMember" xlink:type="locator" xlink:label="us-gaap_OtherCurrentLiabilitiesMember" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_OtherAssetsMember" xlink:type="locator" xlink:label="us-gaap_OtherAssetsMember" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_EmployeeStockMember" xlink:type="locator" xlink:label="us-gaap_EmployeeStockMember" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_SaleOfStockNameOfTransactionDomain" xlink:type="locator" xlink:label="us-gaap_SaleOfStockNameOfTransactionDomain" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_SubsidiarySaleOfStockAxis" xlink:type="locator" xlink:label="us-gaap_SubsidiarySaleOfStockAxis" />
    <loc xlink:href="medp-20161231.xsd#medp_TravelServicesMember" xlink:type="locator" xlink:label="medp_TravelServicesMember" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_BuildingMember" xlink:type="locator" xlink:label="us-gaap_BuildingMember" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_PropertyPlantAndEquipmentTypeDomain" xlink:type="locator" xlink:label="us-gaap_PropertyPlantAndEquipmentTypeDomain" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_PropertyPlantAndEquipmentByTypeAxis" xlink:type="locator" xlink:label="us-gaap_PropertyPlantAndEquipmentByTypeAxis" />
    <loc xlink:href="medp-20161231.xsd#medp_PropertyAndEquipmentNetMember" xlink:type="locator" xlink:label="medp_PropertyAndEquipmentNetMember" />
    <loc xlink:href="medp-20161231.xsd#medp_ChiefExecutiveOfficerAndImmediateFamilyMember" xlink:type="locator" xlink:label="medp_ChiefExecutiveOfficerAndImmediateFamilyMember" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ChiefExecutiveOfficerMember" xlink:type="locator" xlink:label="us-gaap_ChiefExecutiveOfficerMember" />
    <loc xlink:href="medp-20161231.xsd#medp_LeasedRealEstateMember" xlink:type="locator" xlink:label="medp_LeasedRealEstateMember" />
    <loc xlink:href="medp-20161231.xsd#medp_MedpaceInvestorsLLCMember" xlink:type="locator" xlink:label="medp_MedpaceInvestorsLLCMember" />
    <loc xlink:href="medp-20161231.xsd#medp_LIBTherapeuticsCompanyMember" xlink:type="locator" xlink:label="medp_LIBTherapeuticsCompanyMember" />
    <loc xlink:href="medp-20161231.xsd#medp_CymabayTherapeuticsCompanyMember" xlink:type="locator" xlink:label="medp_CymabayTherapeuticsCompanyMember" />
    <loc xlink:href="medp-20161231.xsd#medp_XenonClinicalBiopharmaceuticalCompanyMember" xlink:type="locator" xlink:label="medp_XenonClinicalBiopharmaceuticalCompanyMember" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_OtherNonoperatingIncomeExpenseMember" xlink:type="locator" xlink:label="us-gaap_OtherNonoperatingIncomeExpenseMember" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_IncomeStatementLocationDomain" xlink:type="locator" xlink:label="us-gaap_IncomeStatementLocationDomain" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_IncomeStatementLocationAxis" xlink:type="locator" xlink:label="us-gaap_IncomeStatementLocationAxis" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_PredecessorMember" xlink:type="locator" xlink:label="us-gaap_PredecessorMember" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ScenarioUnspecifiedDomain" xlink:type="locator" xlink:label="us-gaap_ScenarioUnspecifiedDomain" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_StatementScenarioAxis" xlink:type="locator" xlink:label="us-gaap_StatementScenarioAxis" />
    <loc xlink:href="medp-20161231.xsd#medp_MXIIAssociatesLLCMember" xlink:type="locator" xlink:label="medp_MXIIAssociatesLLCMember" />
    <loc xlink:href="medp-20161231.xsd#medp_CoherusBioSciencesIncMember" xlink:type="locator" xlink:label="medp_CoherusBioSciencesIncMember" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_MaximumMember" xlink:type="locator" xlink:label="us-gaap_MaximumMember" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_RangeMember" xlink:type="locator" xlink:label="us-gaap_RangeMember" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_RangeAxis" xlink:type="locator" xlink:label="us-gaap_RangeAxis" />
    <loc xlink:href="medp-20161231.xsd#medp_SymplmedPharmaceuticalsLLCMember" xlink:type="locator" xlink:label="medp_SymplmedPharmaceuticalsLLCMember" />
    <loc xlink:href="medp-20161231.xsd#medp_RelatedPartyServiceAgreementsMember" xlink:type="locator" xlink:label="medp_RelatedPartyServiceAgreementsMember" />
    <loc xlink:href="medp-20161231.xsd#medp_CinvenCapitalManagementVGeneralPartnerLimitedMember" xlink:type="locator" xlink:label="medp_CinvenCapitalManagementVGeneralPartnerLimitedMember" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_RelatedPartyDomain" xlink:type="locator" xlink:label="us-gaap_RelatedPartyDomain" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_RelatedPartyTransactionsByRelatedPartyAxis" xlink:type="locator" xlink:label="us-gaap_RelatedPartyTransactionsByRelatedPartyAxis" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_OtherNoncurrentAssetsMember" xlink:type="locator" xlink:label="us-gaap_OtherNoncurrentAssetsMember" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_PrepaidExpensesAndOtherCurrentAssetsMember" xlink:type="locator" xlink:label="us-gaap_PrepaidExpensesAndOtherCurrentAssetsMember" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_BalanceSheetLocationDomain" xlink:type="locator" xlink:label="us-gaap_BalanceSheetLocationDomain" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_BalanceSheetLocationAxis" xlink:type="locator" xlink:label="us-gaap_BalanceSheetLocationAxis" />
    <loc xlink:href="medp-20161231.xsd#medp_EmployeeLoansMember" xlink:type="locator" xlink:label="medp_EmployeeLoansMember" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_RelatedPartyTransactionDomain" xlink:type="locator" xlink:label="us-gaap_RelatedPartyTransactionDomain" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_RelatedPartyTransactionAxis" xlink:type="locator" xlink:label="us-gaap_RelatedPartyTransactionAxis" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable" xlink:type="locator" xlink:label="us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_RelatedPartyTransactionLineItems" xlink:type="locator" xlink:label="us-gaap_RelatedPartyTransactionLineItems" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="us-gaap_RelatedPartyTransactionLineItems" xlink:to="us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable" order="10010.00" priority="2" use="optional" xbrldt:contextElement="segment" xbrldt:closed="true" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable" xlink:to="us-gaap_RelatedPartyTransactionAxis" order="10040.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_RelatedPartyTransactionAxis" xlink:to="us-gaap_RelatedPartyTransactionDomain" order="10060.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_RelatedPartyTransactionDomain" xlink:to="medp_EmployeeLoansMember" order="10080.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable" xlink:to="us-gaap_BalanceSheetLocationAxis" order="10110.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_BalanceSheetLocationAxis" xlink:to="us-gaap_BalanceSheetLocationDomain" order="10130.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_BalanceSheetLocationDomain" xlink:to="us-gaap_PrepaidExpensesAndOtherCurrentAssetsMember" order="10150.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_BalanceSheetLocationDomain" xlink:to="us-gaap_OtherNoncurrentAssetsMember" order="10170.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable" xlink:to="us-gaap_RelatedPartyTransactionsByRelatedPartyAxis" order="10180.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_RelatedPartyTransactionsByRelatedPartyAxis" xlink:to="us-gaap_RelatedPartyDomain" order="10200.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_RelatedPartyDomain" xlink:to="medp_CinvenCapitalManagementVGeneralPartnerLimitedMember" order="10220.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_RelatedPartyTransactionDomain" xlink:to="medp_RelatedPartyServiceAgreementsMember" order="10330.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_RelatedPartyDomain" xlink:to="medp_SymplmedPharmaceuticalsLLCMember" order="10440.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable" xlink:to="us-gaap_RangeAxis" order="10510.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_RangeAxis" xlink:to="us-gaap_RangeMember" order="10530.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_RangeMember" xlink:to="us-gaap_MaximumMember" order="10550.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_RelatedPartyDomain" xlink:to="medp_CoherusBioSciencesIncMember" order="10620.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_RelatedPartyDomain" xlink:to="medp_MXIIAssociatesLLCMember" order="10640.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable" xlink:to="us-gaap_StatementScenarioAxis" order="10810.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_StatementScenarioAxis" xlink:to="us-gaap_ScenarioUnspecifiedDomain" order="10830.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ScenarioUnspecifiedDomain" xlink:to="us-gaap_PredecessorMember" order="10850.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable" xlink:to="us-gaap_IncomeStatementLocationAxis" order="11140.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_IncomeStatementLocationAxis" xlink:to="us-gaap_IncomeStatementLocationDomain" order="11160.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_IncomeStatementLocationDomain" xlink:to="us-gaap_OtherNonoperatingIncomeExpenseMember" order="11180.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_RelatedPartyDomain" xlink:to="medp_XenonClinicalBiopharmaceuticalCompanyMember" order="11330.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_RelatedPartyDomain" xlink:to="medp_CymabayTherapeuticsCompanyMember" order="11840.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_RelatedPartyDomain" xlink:to="medp_LIBTherapeuticsCompanyMember" order="11940.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_RelatedPartyDomain" xlink:to="medp_MedpaceInvestorsLLCMember" order="12040.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_RelatedPartyTransactionDomain" xlink:to="medp_LeasedRealEstateMember" order="12130.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_RelatedPartyDomain" xlink:to="us-gaap_ChiefExecutiveOfficerMember" order="12350.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_RelatedPartyDomain" xlink:to="medp_ChiefExecutiveOfficerAndImmediateFamilyMember" order="12820.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_BalanceSheetLocationDomain" xlink:to="medp_PropertyAndEquipmentNetMember" order="13070.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable" xlink:to="us-gaap_PropertyPlantAndEquipmentByTypeAxis" order="13080.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_PropertyPlantAndEquipmentByTypeAxis" xlink:to="us-gaap_PropertyPlantAndEquipmentTypeDomain" order="13100.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_PropertyPlantAndEquipmentTypeDomain" xlink:to="us-gaap_BuildingMember" order="13120.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_RelatedPartyTransactionDomain" xlink:to="medp_TravelServicesMember" order="13270.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable" xlink:to="us-gaap_SubsidiarySaleOfStockAxis" order="13280.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_SubsidiarySaleOfStockAxis" xlink:to="us-gaap_SaleOfStockNameOfTransactionDomain" order="13300.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_SaleOfStockNameOfTransactionDomain" xlink:to="us-gaap_EmployeeStockMember" order="13320.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_BalanceSheetLocationDomain" xlink:to="us-gaap_OtherAssetsMember" order="13480.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_BalanceSheetLocationDomain" xlink:to="us-gaap_OtherCurrentLiabilitiesMember" order="13500.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_BalanceSheetLocationDomain" xlink:to="us-gaap_OtherNoncurrentLiabilitiesMember" order="13520.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_RelatedPartyDomain" xlink:to="medp_FormerOwnerMember" order="13610.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable" xlink:to="us-gaap_IncomeTaxAuthorityAxis" order="13640.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_IncomeTaxAuthorityAxis" xlink:to="us-gaap_IncomeTaxAuthorityDomain" order="13660.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_IncomeTaxAuthorityDomain" xlink:to="us-gaap_StateAndLocalJurisdictionMember" order="13680.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_IncomeTaxAuthorityDomain" xlink:to="medp_OtherTaxingAuthoritiesMember" order="13720.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_RelatedPartyTransactionLineItems" xlink:to="us-gaap_DueFromEmployeesCurrent" order="13770.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_RelatedPartyTransactionLineItems" xlink:to="us-gaap_DueFromEmployeesNoncurrent" order="13830.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_RelatedPartyTransactionLineItems" xlink:to="us-gaap_ManagementFeeExpense" order="13920.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_RelatedPartyTransactionLineItems" xlink:to="us-gaap_TravelAndEntertainmentExpense" order="14060.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_RelatedPartyTransactionLineItems" xlink:to="us-gaap_AccountsPayableRelatedPartiesCurrent" order="14200.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_RelatedPartyTransactionLineItems" xlink:to="us-gaap_NoninterestExpenseDirectorsFees" order="14320.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_RelatedPartyTransactionLineItems" xlink:to="us-gaap_RelatedPartyTransactionExpensesFromTransactionsWithRelatedParty" order="14450.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_RelatedPartyTransactionLineItems" xlink:to="us-gaap_RevenueFromRelatedParties" order="14520.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_RelatedPartyTransactionLineItems" xlink:to="us-gaap_AccountsReceivableRelatedPartiesCurrent" order="14700.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_RelatedPartyTransactionLineItems" xlink:to="us-gaap_Investments" order="14890.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_RelatedPartyTransactionLineItems" xlink:to="medp_PercentageOfSalesCommission" order="14990.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_RelatedPartyTransactionLineItems" xlink:to="medp_ClinicalTrialServicesAgreementNoticePeriodPriorToCancellation" order="15090.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_RelatedPartyTransactionLineItems" xlink:to="medp_CommissionsRelatedParty" order="15190.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_RelatedPartyTransactionLineItems" xlink:to="medp_ReimbursedOutOfPocketRevenueWithRelatedParties" order="15490.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_RelatedPartyTransactionLineItems" xlink:to="medp_ReimbursedOutOfPocketExpensesWithRelatedParties" order="15650.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_RelatedPartyTransactionLineItems" xlink:to="medp_UnbilledContractReceivablesCurrentWithRelatedParties" order="15810.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_RelatedPartyTransactionLineItems" xlink:to="us-gaap_DeferredRevenueCurrent" order="15930.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_RelatedPartyTransactionLineItems" xlink:to="medp_PreFundedStudyCostsWithRelatedParties" order="16050.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_RelatedPartyTransactionLineItems" xlink:to="us-gaap_RelatedPartyTaxExpenseDueToAffiliatesCurrent" order="17080.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_RelatedPartyTransactionLineItems" xlink:to="us-gaap_LesseeLeasingArrangementsOperatingLeasesTermOfContract" order="17390.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_RelatedPartyTransactionLineItems" xlink:to="medp_LeaseExpirationMonthAndYear" order="17490.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_RelatedPartyTransactionLineItems" xlink:to="medp_NumberOfLeaseRenewalOptions" order="17590.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_RelatedPartyTransactionLineItems" xlink:to="us-gaap_LesseeLeasingArrangementsOperatingLeasesRenewalTerm" order="17690.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_RelatedPartyTransactionLineItems" xlink:to="us-gaap_LeaseAndRentalExpense" order="17790.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_RelatedPartyTransactionLineItems" xlink:to="us-gaap_OperatingLeasesRentExpenseNet" order="17890.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_RelatedPartyTransactionLineItems" xlink:to="medp_OperatingLeasesLeaseBasis" order="18050.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_RelatedPartyTransactionLineItems" xlink:to="medp_NumberOfLeaseAgreements" order="18180.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_RelatedPartyTransactionLineItems" xlink:to="medp_NumberOfBuilding" order="18280.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_RelatedPartyTransactionLineItems" xlink:to="medp_LeaseOccupancyYear" order="18380.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_RelatedPartyTransactionLineItems" xlink:to="medp_LeaseExpirationYear" order="18480.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_RelatedPartyTransactionLineItems" xlink:to="us-gaap_AccretionExpense" order="18880.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_RelatedPartyTransactionLineItems" xlink:to="us-gaap_CapitalLeaseObligationsCurrent" order="19040.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_RelatedPartyTransactionLineItems" xlink:to="us-gaap_CapitalLeaseObligationsNoncurrent" order="19160.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_RelatedPartyTransactionLineItems" xlink:to="us-gaap_CapitalLeasesBalanceSheetAssetsByMajorClassNet" order="19280.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_RelatedPartyTransactionLineItems" xlink:to="us-gaap_StockIssuedDuringPeriodSharesEmployeeStockOwnershipPlan" order="19620.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_RelatedPartyTransactionLineItems" xlink:to="us-gaap_AllocatedShareBasedCompensationExpense" order="19660.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_RelatedPartyTransactionLineItems" xlink:to="us-gaap_DueFromRelatedPartiesCurrent" order="19730.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_RelatedPartyTransactionLineItems" xlink:to="us-gaap_DueFromRelatedPartiesNoncurrent" order="19810.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_RelatedPartyTransactionLineItems" xlink:to="us-gaap_DueToRelatedPartiesCurrent" order="19890.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_RelatedPartyTransactionLineItems" xlink:to="us-gaap_DueToRelatedPartiesNoncurrent" order="19970.00" priority="2" use="optional" />
  </definitionLink>
  <roleRef roleURI="http://www.medpace.com/20161231/taxonomy/role/DisclosureAcquisitionAndIntegrationExpensesAdditionalInformationDetails" xlink:href="medp-20161231.xsd#Role_DisclosureAcquisitionAndIntegrationExpensesAdditionalInformationDetails" xlink:type="simple" />
  <definitionLink xlink:type="extended" xlink:role="http://www.medpace.com/20161231/taxonomy/role/DisclosureAcquisitionAndIntegrationExpensesAdditionalInformationDetails">
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_BusinessCombinationIntegrationRelatedCosts" xlink:type="locator" xlink:label="us-gaap_BusinessCombinationIntegrationRelatedCosts" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_PredecessorMember" xlink:type="locator" xlink:label="us-gaap_PredecessorMember" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ScenarioUnspecifiedDomain" xlink:type="locator" xlink:label="us-gaap_ScenarioUnspecifiedDomain" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_StatementScenarioAxis" xlink:type="locator" xlink:label="us-gaap_StatementScenarioAxis" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_StatementTable" xlink:type="locator" xlink:label="us-gaap_StatementTable" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_StatementLineItems" xlink:type="locator" xlink:label="us-gaap_StatementLineItems" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="us-gaap_StatementLineItems" xlink:to="us-gaap_StatementTable" order="10010.00" priority="2" use="optional" xbrldt:contextElement="segment" xbrldt:closed="true" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="us-gaap_StatementTable" xlink:to="us-gaap_StatementScenarioAxis" order="10040.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_StatementScenarioAxis" xlink:to="us-gaap_ScenarioUnspecifiedDomain" order="10060.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ScenarioUnspecifiedDomain" xlink:to="us-gaap_PredecessorMember" order="10080.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_StatementLineItems" xlink:to="us-gaap_BusinessCombinationIntegrationRelatedCosts" order="10110.00" priority="2" use="optional" />
  </definitionLink>
  <roleRef roleURI="http://www.medpace.com/20161231/taxonomy/role/DisclosureEntityWideDisclosuresAdditionalInformationDetails" xlink:href="medp-20161231.xsd#Role_DisclosureEntityWideDisclosuresAdditionalInformationDetails" xlink:type="simple" />
  <definitionLink xlink:type="extended" xlink:role="http://www.medpace.com/20161231/taxonomy/role/DisclosureEntityWideDisclosuresAdditionalInformationDetails">
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ConcentrationRiskPercentage1" xlink:type="locator" xlink:label="us-gaap_ConcentrationRiskPercentage1" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_PredecessorMember" xlink:type="locator" xlink:label="us-gaap_PredecessorMember" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ScenarioUnspecifiedDomain" xlink:type="locator" xlink:label="us-gaap_ScenarioUnspecifiedDomain" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_StatementScenarioAxis" xlink:type="locator" xlink:label="us-gaap_StatementScenarioAxis" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ProductConcentrationRiskMember" xlink:type="locator" xlink:label="us-gaap_ProductConcentrationRiskMember" />
    <loc xlink:href="medp-20161231.xsd#medp_LaboratoryServicesMember" xlink:type="locator" xlink:label="medp_LaboratoryServicesMember" />
    <loc xlink:href="medp-20161231.xsd#medp_ClinicalResearchServiceMember" xlink:type="locator" xlink:label="medp_ClinicalResearchServiceMember" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ProductsAndServicesDomain" xlink:type="locator" xlink:label="us-gaap_ProductsAndServicesDomain_2" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ProductsAndServicesDomain" xlink:type="locator" xlink:label="us-gaap_ProductsAndServicesDomain" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ProductOrServiceAxis" xlink:type="locator" xlink:label="us-gaap_ProductOrServiceAxis" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_MaximumMember" xlink:type="locator" xlink:label="us-gaap_MaximumMember" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_RangeMember" xlink:type="locator" xlink:label="us-gaap_RangeMember" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_RangeAxis" xlink:type="locator" xlink:label="us-gaap_RangeAxis" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_GeographicConcentrationRiskMember" xlink:type="locator" xlink:label="us-gaap_GeographicConcentrationRiskMember" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ConcentrationRiskTypeDomain" xlink:type="locator" xlink:label="us-gaap_ConcentrationRiskTypeDomain_2" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ConcentrationRiskTypeDomain" xlink:type="locator" xlink:label="us-gaap_ConcentrationRiskTypeDomain" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ConcentrationRiskByTypeAxis" xlink:type="locator" xlink:label="us-gaap_ConcentrationRiskByTypeAxis" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_SalesRevenueServicesNetMember" xlink:type="locator" xlink:label="us-gaap_SalesRevenueServicesNetMember" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ConcentrationRiskBenchmarkDomain" xlink:type="locator" xlink:label="us-gaap_ConcentrationRiskBenchmarkDomain_2" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ConcentrationRiskBenchmarkDomain" xlink:type="locator" xlink:label="us-gaap_ConcentrationRiskBenchmarkDomain" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ConcentrationRiskByBenchmarkAxis" xlink:type="locator" xlink:label="us-gaap_ConcentrationRiskByBenchmarkAxis" />
    <loc xlink:href="http://xbrl.sec.gov/country/2016/country-2016-01-31.xsd#country_US" xlink:type="locator" xlink:label="country_US" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_SegmentGeographicalDomain" xlink:type="locator" xlink:label="us-gaap_SegmentGeographicalDomain" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_StatementGeographicalAxis" xlink:type="locator" xlink:label="us-gaap_StatementGeographicalAxis" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable" xlink:type="locator" xlink:label="us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_SegmentReportingInformationLineItems" xlink:type="locator" xlink:label="us-gaap_SegmentReportingInformationLineItems" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="us-gaap_SegmentReportingInformationLineItems" xlink:to="us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable" order="10010.00" priority="2" use="optional" xbrldt:contextElement="segment" xbrldt:closed="true" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable" xlink:to="us-gaap_StatementGeographicalAxis" order="10040.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_StatementGeographicalAxis" xlink:to="us-gaap_SegmentGeographicalDomain" order="10060.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_SegmentGeographicalDomain" xlink:to="country_US" order="10080.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable" xlink:to="us-gaap_ConcentrationRiskByBenchmarkAxis" order="10090.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="us-gaap_ConcentrationRiskByBenchmarkAxis" xlink:to="us-gaap_ConcentrationRiskBenchmarkDomain_2" order="10110.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_ConcentrationRiskByBenchmarkAxis" xlink:to="us-gaap_ConcentrationRiskBenchmarkDomain" order="10110.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ConcentrationRiskBenchmarkDomain" xlink:to="us-gaap_SalesRevenueServicesNetMember" order="10130.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable" xlink:to="us-gaap_ConcentrationRiskByTypeAxis" order="10160.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="us-gaap_ConcentrationRiskByTypeAxis" xlink:to="us-gaap_ConcentrationRiskTypeDomain_2" order="10180.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_ConcentrationRiskByTypeAxis" xlink:to="us-gaap_ConcentrationRiskTypeDomain" order="10180.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ConcentrationRiskTypeDomain" xlink:to="us-gaap_GeographicConcentrationRiskMember" order="10200.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable" xlink:to="us-gaap_RangeAxis" order="10230.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_RangeAxis" xlink:to="us-gaap_RangeMember" order="10250.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_RangeMember" xlink:to="us-gaap_MaximumMember" order="10270.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable" xlink:to="us-gaap_ProductOrServiceAxis" order="10280.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="us-gaap_ProductOrServiceAxis" xlink:to="us-gaap_ProductsAndServicesDomain_2" order="10300.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_ProductOrServiceAxis" xlink:to="us-gaap_ProductsAndServicesDomain" order="10300.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ProductsAndServicesDomain" xlink:to="medp_ClinicalResearchServiceMember" order="10320.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ProductsAndServicesDomain" xlink:to="medp_LaboratoryServicesMember" order="10340.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ConcentrationRiskTypeDomain" xlink:to="us-gaap_ProductConcentrationRiskMember" order="10700.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable" xlink:to="us-gaap_StatementScenarioAxis" order="10850.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_StatementScenarioAxis" xlink:to="us-gaap_ScenarioUnspecifiedDomain" order="10870.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_ScenarioUnspecifiedDomain" xlink:to="us-gaap_PredecessorMember" order="10890.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_SegmentReportingInformationLineItems" xlink:to="us-gaap_ConcentrationRiskPercentage1" order="10940.00" priority="2" use="optional" />
  </definitionLink>
  <roleRef roleURI="http://www.medpace.com/20161231/taxonomy/role/DisclosureEntityWideDisclosuresSummaryOfPropertyAndEquipmentNetByGeographicRegionDetails" xlink:href="medp-20161231.xsd#Role_DisclosureEntityWideDisclosuresSummaryOfPropertyAndEquipmentNetByGeographicRegionDetails" xlink:type="simple" />
  <definitionLink xlink:type="extended" xlink:role="http://www.medpace.com/20161231/taxonomy/role/DisclosureEntityWideDisclosuresSummaryOfPropertyAndEquipmentNetByGeographicRegionDetails">
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_PropertyPlantAndEquipmentNet" xlink:type="locator" xlink:label="us-gaap_PropertyPlantAndEquipmentNet" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_PropertyPlantAndEquipmentNetAbstract" xlink:type="locator" xlink:label="us-gaap_PropertyPlantAndEquipmentNetAbstract" />
    <loc xlink:href="medp-20161231.xsd#medp_OtherCountriesMember" xlink:type="locator" xlink:label="medp_OtherCountriesMember" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_EuropeMember" xlink:type="locator" xlink:label="us-gaap_EuropeMember" />
    <loc xlink:href="medp-20161231.xsd#medp_OtherEuropeCountriesMember" xlink:type="locator" xlink:label="medp_OtherEuropeCountriesMember" />
    <loc xlink:href="http://xbrl.sec.gov/country/2016/country-2016-01-31.xsd#country_BE" xlink:type="locator" xlink:label="country_BE" />
    <loc xlink:href="http://xbrl.sec.gov/country/2016/country-2016-01-31.xsd#country_US" xlink:type="locator" xlink:label="country_US" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_SegmentGeographicalDomain" xlink:type="locator" xlink:label="us-gaap_SegmentGeographicalDomain" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2016/elts/us-gaap-2016-01-31.xsd#us-gaap_StatementGeographicalAxis" xlink:type="locator" xlink:label="us-gaap_StatementGeographicalAxis" />
    <loc xlink:href="http://xbrl.sec.gov/dei/2014/dei-2014-01-31.xsd#dei_EntitiesTable" xlink:type="locator" xlink:label="dei_EntitiesTable" />
    <loc xlink:href="http://xbrl.sec.gov/dei/2014/dei-2014-01-31.xsd#dei_EntityInformationLineItems" xlink:type="locator" xlink:label="dei_EntityInformationLineItems" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="dei_EntityInformationLineItems" xlink:to="dei_EntitiesTable" order="10010.00" priority="2" use="optional" xbrldt:contextElement="segment" xbrldt:closed="true" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="dei_EntitiesTable" xlink:to="us-gaap_StatementGeographicalAxis" order="10040.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="us-gaap_StatementGeographicalAxis" xlink:to="us-gaap_SegmentGeographicalDomain" order="10060.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_SegmentGeographicalDomain" xlink:to="country_US" order="10080.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_SegmentGeographicalDomain" xlink:to="country_BE" order="10100.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_SegmentGeographicalDomain" xlink:to="medp_OtherEuropeCountriesMember" order="10120.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_SegmentGeographicalDomain" xlink:to="us-gaap_EuropeMember" order="10140.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_SegmentGeographicalDomain" xlink:to="medp_OtherCountriesMember" order="10160.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="dei_EntityInformationLineItems" xlink:to="us-gaap_PropertyPlantAndEquipmentNetAbstract" order="10190.00" priority="2" use="optional" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="us-gaap_PropertyPlantAndEquipmentNetAbstract" xlink:to="us-gaap_PropertyPlantAndEquipmentNet" order="10270.00" priority="2" use="optional" />
  </definitionLink>
</linkbase>
