﻿<?xml version="1.0" encoding="utf-8"?>
<Return xmlns="http://www.irs.gov/efile" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.irs.gov/efile" returnVersion="2023v6.0">
  <ReturnHeader binaryAttachmentCnt="0">
    <ReturnTs>2025-08-04T14:17:04-05:00</ReturnTs>
    <TaxPeriodEndDt>2024-09-30</TaxPeriodEndDt>
    <ReturnTypeCd>990EZ</ReturnTypeCd>
    <TaxPeriodBeginDt>2023-10-01</TaxPeriodBeginDt>
    <Filer>
      <EIN>822772540</EIN>
      <BusinessName>
        <BusinessNameLine1Txt>SEATTLE CHILDREN'S HOSPITAL</BusinessNameLine1Txt>
        <BusinessNameLine2Txt>(DBA AARON MATTHEW SIDS RESEARCH GUILD)</BusinessNameLine2Txt>
      </BusinessName>
      <BusinessNameControlTxt>SEAT</BusinessNameControlTxt>
      <PhoneNum>2068842351</PhoneNum>
      <USAddress>
        <AddressLine1Txt>PO BOX 5371 MS 818-FI</AddressLine1Txt>
        <CityNm>SEATTLE</CityNm>
        <StateAbbreviationCd>WA</StateAbbreviationCd>
        <ZIPCd>981455005</ZIPCd>
      </USAddress>
    </Filer>
    <BusinessOfficerGrp>
      <PersonNm>AILEEN KELLY</PersonNm>
      <PersonTitleTxt>GUILD ASSN EXECUTIVE DIRECTOR</PersonTitleTxt>
      <PhoneNum>2068842351</PhoneNum>
      <SignatureDt>2025-08-04</SignatureDt>
    </BusinessOfficerGrp>
    <IRSResponsiblePrtyInfoCurrInd>0</IRSResponsiblePrtyInfoCurrInd>
    <TaxYr>2023</TaxYr>
    <BuildTS>2025-03-06 01:10:19Z</BuildTS>
  </ReturnHeader>
  <ReturnData documentCnt="5">
    <IRS990EZ documentId="RetDoc1234200001" referenceDocumentId="RetDoc1051800001 RetDoc2278000001">
      <GroupExemptionNum>8041</GroupExemptionNum>
      <MethodOfAccountingCashInd>X</MethodOfAccountingCashInd>
      <WebsiteAddressTxt>WWW.GIVETOSTOPSIDS.ORG</WebsiteAddressTxt>
      <Organization501c3Ind referenceDocumentId="RetDoc1039100001">X</Organization501c3Ind>
      <TypeOfOrganizationAssocInd>X</TypeOfOrganizationAssocInd>
      <GrossReceiptsAmt>59555</GrossReceiptsAmt>
      <InfoInScheduleOPartIInd>X</InfoInScheduleOPartIInd>
      <ContributionsGiftsGrantsEtcAmt>59555</ContributionsGiftsGrantsEtcAmt>
      <TotalRevenueAmt>59555</TotalRevenueAmt>
      <GrantsAndSimilarAmountsPaidAmt>46500</GrantsAndSimilarAmountsPaidAmt>
      <OtherExpensesTotalAmt>2362</OtherExpensesTotalAmt>
      <TotalExpensesAmt>48862</TotalExpensesAmt>
      <ExcessOrDeficitForYearAmt>10693</ExcessOrDeficitForYearAmt>
      <NetAssetsOrFundBalancesBOYAmt>8415</NetAssetsOrFundBalancesBOYAmt>
      <OtherChangesInNetAssetsAmt>0</OtherChangesInNetAssetsAmt>
      <NetAssetsOrFundBalancesEOYAmt>19108</NetAssetsOrFundBalancesEOYAmt>
      <CashSavingsAndInvestmentsGrp>
        <BOYAmt>8415</BOYAmt>
        <EOYAmt>19108</EOYAmt>
      </CashSavingsAndInvestmentsGrp>
      <Form990TotalAssetsGrp>
        <BOYAmt>8415</BOYAmt>
        <EOYAmt>19108</EOYAmt>
      </Form990TotalAssetsGrp>
      <SumOfTotalLiabilitiesGrp>
        <BOYAmt>0</BOYAmt>
        <EOYAmt>0</EOYAmt>
      </SumOfTotalLiabilitiesGrp>
      <NetAssetsOrFundBalancesGrp>
        <BOYAmt>8415</BOYAmt>
        <EOYAmt>19108</EOYAmt>
      </NetAssetsOrFundBalancesGrp>
      <InfoInScheduleOPartIIIInd>X</InfoInScheduleOPartIIIInd>
      <PrimaryExemptPurposeTxt>THE AARON MATTHEW SIDS RESEARCH GUILD WAS FOUNDED IN 2017 TO SUPPORT SEATTLE CHILDREN'S HOSPITAL (A 501(C)(3) TAX-EXEMPT HOSPITAL). DONATIONS FROM THE AARON MATTHEW SIDS RESEARCH GUILD PRIMARILY PROVIDE SUPPORT FOR RESEARCH INTO SUDDEN INFANT DEATH SYNDROME (SIDS).</PrimaryExemptPurposeTxt>
      <ProgramSrvcAccomplishmentGrp>
        <DescriptionProgramSrvcAccomTxt>THE AARON MATTHEW SIDS RESEARCH GUILD IS A MEMBER OF THE SEATTLE CHILDREN'S GUILD ASSOCIATION, A TAX-EXEMPT FUNDRAISING ENTITY OF SEATTLE CHILDREN'S HOSPITAL. THE HOSPITAL PROVIDES PEDIATRIC PATIENT CARE, MEDICAL RESEARCH, TEACHING OF PEDIATRIC RESIDENTS AND OTHER HEALTHCARE PROVIDERS, AS WELL AS ADVOCACY FOR CHILDREN IN THE PACIFIC NORTHWEST. THE AARON MATTHEW SIDS RESEARCH GUILD WAS NAMED IN HONOR OF AARON MATTHEW KAHAN, SON OF HEATHER KAHAN AND JOHN B. KAHAN, WHO DIED OF SIDS DAYS AFTER HIS BIRTH IN 2003. THE GUILD'S MISSION IS TO ENSURE THAT NO PARENT EVER EXPERIENCES THE LOSS OF A CHILD AGAIN OR WORRIES THEIRS WILL BE NEXT.</DescriptionProgramSrvcAccomTxt>
        <GrantsAndAllocationsAmt>46500</GrantsAndAllocationsAmt>
        <ProgramServiceExpensesAmt>46500</ProgramServiceExpensesAmt>
      </ProgramSrvcAccomplishmentGrp>
      <TotalProgramServiceExpensesAmt>46500</TotalProgramServiceExpensesAmt>
      <OfficerDirectorTrusteeEmplGrp>
        <PersonNm>AILEEN KELLY</PersonNm>
        <TitleTxt>GUILD ASSN EXECUTIVE DIRECTOR</TitleTxt>
        <AverageHrsPerWkDevotedToPosRt>1.00</AverageHrsPerWkDevotedToPosRt>
        <CompensationAmt>0</CompensationAmt>
        <EmployeeBenefitProgramAmt>0</EmployeeBenefitProgramAmt>
        <ExpenseAccountOtherAllwncAmt>0</ExpenseAccountOtherAllwncAmt>
      </OfficerDirectorTrusteeEmplGrp>
      <OfficerDirectorTrusteeEmplGrp>
        <PersonNm>JOHN KAHAN</PersonNm>
        <TitleTxt>PRESIDENT</TitleTxt>
        <AverageHrsPerWkDevotedToPosRt>1.00</AverageHrsPerWkDevotedToPosRt>
        <CompensationAmt>0</CompensationAmt>
        <EmployeeBenefitProgramAmt>0</EmployeeBenefitProgramAmt>
        <ExpenseAccountOtherAllwncAmt>0</ExpenseAccountOtherAllwncAmt>
      </OfficerDirectorTrusteeEmplGrp>
      <OfficerDirectorTrusteeEmplGrp>
        <PersonNm>HEATHER KAHAN</PersonNm>
        <TitleTxt>SECRETARY</TitleTxt>
        <AverageHrsPerWkDevotedToPosRt>1.00</AverageHrsPerWkDevotedToPosRt>
        <CompensationAmt>0</CompensationAmt>
        <EmployeeBenefitProgramAmt>0</EmployeeBenefitProgramAmt>
        <ExpenseAccountOtherAllwncAmt>0</ExpenseAccountOtherAllwncAmt>
      </OfficerDirectorTrusteeEmplGrp>
      <OfficerDirectorTrusteeEmplGrp>
        <PersonNm>GILBERT D WOOTTON</PersonNm>
        <TitleTxt>TREASURER</TitleTxt>
        <AverageHrsPerWkDevotedToPosRt>1.00</AverageHrsPerWkDevotedToPosRt>
        <CompensationAmt>0</CompensationAmt>
        <EmployeeBenefitProgramAmt>0</EmployeeBenefitProgramAmt>
        <ExpenseAccountOtherAllwncAmt>0</ExpenseAccountOtherAllwncAmt>
      </OfficerDirectorTrusteeEmplGrp>
      <InfoInScheduleOPartVInd>X</InfoInScheduleOPartVInd>
      <ActivitiesNotPreviouslyRptInd>0</ActivitiesNotPreviouslyRptInd>
      <ChgMadeToOrgnzngDocNotRptInd>0</ChgMadeToOrgnzngDocNotRptInd>
      <OrganizationHadUBIInd>0</OrganizationHadUBIInd>
      <SubjectToProxyTaxInd>0</SubjectToProxyTaxInd>
      <OrganizationDissolvedEtcInd>0</OrganizationDissolvedEtcInd>
      <DirectIndirectPltclExpendAmt>0</DirectIndirectPltclExpendAmt>
      <MadeLoansToFromOfficersInd>0</MadeLoansToFromOfficersInd>
      <TaxImposedUnderIRC4911Amt>0</TaxImposedUnderIRC4911Amt>
      <TaxImposedUnderIRC4912Amt>0</TaxImposedUnderIRC4912Amt>
      <TaxImposedUnderIRC4955Amt>0</TaxImposedUnderIRC4955Amt>
      <EngagedInExcessBenefitTransInd>0</EngagedInExcessBenefitTransInd>
      <TaxImposedOnOrganizationMgrAmt>0</TaxImposedOnOrganizationMgrAmt>
      <TaxReimbursedByOrganizationAmt>0</TaxReimbursedByOrganizationAmt>
      <ProhibitedTaxShelterTransInd>0</ProhibitedTaxShelterTransInd>
      <BooksInCareOfDetail>
        <BusinessName>
          <BusinessNameLine1Txt>SAMANTHA SLOANE</BusinessNameLine1Txt>
        </BusinessName>
        <USAddress>
          <AddressLine1Txt>818 STEWART ST 8TH FLOOR</AddressLine1Txt>
          <CityNm>SEATTLE</CityNm>
          <StateAbbreviationCd>WA</StateAbbreviationCd>
          <ZIPCd>98101</ZIPCd>
        </USAddress>
        <PhoneNum>2068842351</PhoneNum>
      </BooksInCareOfDetail>
      <ForeignFinancialAccountInd>0</ForeignFinancialAccountInd>
      <ForeignOfficeInd>0</ForeignOfficeInd>
      <DonorAdvisedFndsInd>0</DonorAdvisedFndsInd>
      <OperateHospitalInd>0</OperateHospitalInd>
      <TanningServicesProvidedInd>0</TanningServicesProvidedInd>
      <RelatedOrganizationCtrlEntInd>0</RelatedOrganizationCtrlEntInd>
      <PoliticalCampaignActyInd>0</PoliticalCampaignActyInd>
      <LobbyingActivitiesInd>0</LobbyingActivitiesInd>
      <SchoolOperatingInd>0</SchoolOperatingInd>
      <TrnsfrExmptNonChrtblRltdOrgInd>0</TrnsfrExmptNonChrtblRltdOrgInd>
      <PartVIOfCompOfHghstPdEmplTxt>NONE</PartVIOfCompOfHghstPdEmplTxt>
      <PartVIHghstPdCntrctProfSrvcTxt>NONE</PartVIHghstPdCntrctProfSrvcTxt>
      <FiledScheduleAInd>1</FiledScheduleAInd>
    </IRS990EZ>
    <IRS990ScheduleA documentId="RetDoc1039100001">
      <PublicOrganization170Ind>X</PublicOrganization170Ind>
      <GiftsGrantsContriRcvd170Grp>
        <CurrentTaxYearMinus4YearsAmt>36455</CurrentTaxYearMinus4YearsAmt>
        <CurrentTaxYearMinus3YearsAmt>84010</CurrentTaxYearMinus3YearsAmt>
        <CurrentTaxYearMinus2YearsAmt>864966</CurrentTaxYearMinus2YearsAmt>
        <CurrentTaxYearMinus1YearAmt>44663</CurrentTaxYearMinus1YearAmt>
        <CurrentTaxYearAmt>59555</CurrentTaxYearAmt>
        <TotalAmt>1089649</TotalAmt>
      </GiftsGrantsContriRcvd170Grp>
      <TotalCalendarYear170Grp>
        <CurrentTaxYearMinus4YearsAmt>36455</CurrentTaxYearMinus4YearsAmt>
        <CurrentTaxYearMinus3YearsAmt>84010</CurrentTaxYearMinus3YearsAmt>
        <CurrentTaxYearMinus2YearsAmt>864966</CurrentTaxYearMinus2YearsAmt>
        <CurrentTaxYearMinus1YearAmt>44663</CurrentTaxYearMinus1YearAmt>
        <CurrentTaxYearAmt>59555</CurrentTaxYearAmt>
        <TotalAmt>1089649</TotalAmt>
      </TotalCalendarYear170Grp>
      <SubstantialContributorsTotAmt>742276</SubstantialContributorsTotAmt>
      <PublicSupportTotal170Amt>347373</PublicSupportTotal170Amt>
      <GrossInvestmentIncome170Grp>
        <CurrentTaxYearMinus4YearsAmt>25</CurrentTaxYearMinus4YearsAmt>
        <CurrentTaxYearMinus3YearsAmt>23</CurrentTaxYearMinus3YearsAmt>
        <CurrentTaxYearMinus2YearsAmt>77</CurrentTaxYearMinus2YearsAmt>
        <CurrentTaxYearMinus1YearAmt>10</CurrentTaxYearMinus1YearAmt>
        <TotalAmt>135</TotalAmt>
      </GrossInvestmentIncome170Grp>
      <UnrelatedBusinessNetIncm170Grp>
        <CurrentTaxYearMinus4YearsAmt>2976</CurrentTaxYearMinus4YearsAmt>
        <CurrentTaxYearMinus2YearsAmt>3800</CurrentTaxYearMinus2YearsAmt>
        <TotalAmt>6776</TotalAmt>
      </UnrelatedBusinessNetIncm170Grp>
      <TotalSupportAmt>1096560</TotalSupportAmt>
      <PublicSupportCY170Pct>0.31680</PublicSupportCY170Pct>
      <PublicSupportPY170Pct>0.37460</PublicSupportPY170Pct>
      <ThirtyThrPctSuprtTestsPY170Ind>X</ThirtyThrPctSuprtTestsPY170Ind>
      <Form990ScheduleAPartVIGrp>
        <FormAndLineReferenceDesc>PART II, LINE 9:</FormAndLineReferenceDesc>
        <ExplanationTxt>LINE 9 REPRESENTS ACTIVITIES THAT ARE PART OF THE ORGANIZATION'S FUNDRAISING EFFORTS. THE PORTION OF GROSS REVENUE THAT IS ALLOCATED TOWARDS CONTRIBUTIONS IS REPORTED ON LINE 1 AS GIFTS, GRANTS, AND CONTRIBUTIONS. LINE 9 DOES NOT REPRESENT AMOUNTS SUBJECT TO UNRELATED BUSINESS INCOME TAX.</ExplanationTxt>
      </Form990ScheduleAPartVIGrp>
    </IRS990ScheduleA>
    <IRS990ScheduleB documentId="RetDoc1234500001">
      <ContributorInformationGrp>
        <ContributorNum>RESTRICTED</ContributorNum>
        <ContributorBusinessName>
          <BusinessNameLine1>RESTRICTED</BusinessNameLine1>
        </ContributorBusinessName>
        <ContributorUSAddress>
          <AddressLine1>RESTRICTED</AddressLine1>
          <AddressLine2>RESTRICTED</AddressLine2>
          <City>RESTRICTED</City>
          <State>RESTRICTED</State>
          <ZIPCode>RESTRICTED</ZIPCode>
        </ContributorUSAddress>
        <TotalContributionsAmt>RESTRICTED</TotalContributionsAmt>
      </ContributorInformationGrp>
    </IRS990ScheduleB>
    <IRS990ScheduleO documentId="RetDoc1051800001">
      <SupplementalInformationDetail>
        <FormAndLineReferenceDesc>FORM 990-EZ, PART I, LINE 10 - GRANTS AND SIMILAR AMOUNTS PAID</FormAndLineReferenceDesc>
        <ExplanationTxt>ACTIVITY CLASSIFICATION: SIDS RESEARCH FELLOW FUND. GRANTEE NAME: SEATTLE CHILDREN'S GUILD ASSOCIATION. GRANTEE ADDRESS: PO BOX 5371, MS: 818-FI SEATTLE, WA 98145-5005. GRANTEE RELATIONSHIP: NONE. AMOUNT GIVEN: 46,500.</ExplanationTxt>
      </SupplementalInformationDetail>
      <SupplementalInformationDetail>
        <FormAndLineReferenceDesc>FORM 990-EZ, PART I, LINE 16 - OTHER EXPENSES</FormAndLineReferenceDesc>
        <ExplanationTxt>DESCRIPTION: CREDIT CARD &amp; BANK FEES. AMOUNT: 15. DESCRIPTION: OFFICE EXPENSES &amp; SUPPLIES. AMOUNT: 2,347. TOTAL TO FORM 990-EZ, LINE 16: 2,362.</ExplanationTxt>
      </SupplementalInformationDetail>
    </IRS990ScheduleO>
    <TransferPrsnlBnftContractsDecl documentId="RetDoc2278000001">
      <DeclarationDesc>THE ORGANIZATION DID NOT, DURING THE YEAR, RECEIVE ANY FUNDS, DIRECTLY,OR INDIRECTLY, TO PAY PREMIUMS ON A PERSONAL BENEFIT CONTRACT.THE ORGANIZATION, DID NOT, DURING THE YEAR, PAY ANY PREMIUMS, DIRECTLY,OR INDIRECTLY, ON A PERSONAL BENEFIT CONTRACT.</DeclarationDesc>
    </TransferPrsnlBnftContractsDecl>
  </ReturnData>
</Return>