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  <xs:element id="iclr_ComputerEquipmentAndCapitalizedSoftwareMember" abstract="true" name="ComputerEquipmentAndCapitalizedSoftwareMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
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  <xs:element id="iclr_TopClientMember" abstract="true" name="TopClientMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="iclr_CompensationRelatedCostsShareBasedPaymentsDisclosureLineItems" abstract="true" name="CompensationRelatedCostsShareBasedPaymentsDisclosureLineItems" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:stringItemType"/>
  <xs:element id="iclr_ScheduleOfComponentsOfIncomeBeforeIncomeTaxExpenseBenefitLineItems" abstract="true" name="ScheduleOfComponentsOfIncomeBeforeIncomeTaxExpenseBenefitLineItems" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:stringItemType"/>
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</xs:schema>
