<?xml version="1.0" encoding="utf-8"?>
<Return returnVersion="2023v5.0" xmlns="http://www.irs.gov/efile" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
  <ReturnHeader binaryAttachmentCnt="0">
    <ReturnTs>2024-05-06T08:52:30-07:00</ReturnTs>
    <TaxPeriodEndDt>2023-12-31</TaxPeriodEndDt>
    <PreparerFirmGrp>
      <PreparerFirmName>
        <BusinessNameLine1Txt>IAMAW</BusinessNameLine1Txt>
      </PreparerFirmName>
      <PreparerUSAddress>
        <AddressLine1Txt>9000 Machinists Place</AddressLine1Txt>
        <CityNm>Upper Marlboro</CityNm>
        <StateAbbreviationCd>MD</StateAbbreviationCd>
        <ZIPCd>20772</ZIPCd>
      </PreparerUSAddress>
    </PreparerFirmGrp>
    <ReturnTypeCd>990EZ</ReturnTypeCd>
    <TaxPeriodBeginDt>2023-01-01</TaxPeriodBeginDt>
    <Filer>
      <EIN>912086120</EIN>
      <BusinessName>
        <BusinessNameLine1Txt>INTERNATIONAL ASSOCIATION OF MACHINISTS &amp; AEROSPACE WORKERS</BusinessNameLine1Txt>
      </BusinessName>
      <BusinessNameControlTxt>INTE</BusinessNameControlTxt>
      <PhoneNum>6034220306</PhoneNum>
      <USAddress>
        <AddressLine1Txt>15 Hiltons Lane</AddressLine1Txt>
        <CityNm>Rochester</CityNm>
        <StateAbbreviationCd>NH</StateAbbreviationCd>
        <ZIPCd>03868</ZIPCd>
      </USAddress>
    </Filer>
    <BusinessOfficerGrp>
      <PersonNm>Brianne Martinen</PersonNm>
      <PersonTitleTxt>Secretary Treasurer</PersonTitleTxt>
      <PhoneNum>6034220306</PhoneNum>
      <SignatureDt>2024-05-06</SignatureDt>
      <DiscussWithPaidPreparerInd>1</DiscussWithPaidPreparerInd>
    </BusinessOfficerGrp>
    <SigningOfficerGrp>
      <PersonFullName>
        <PersonFirstNm>Brianne</PersonFirstNm>
        <PersonLastNm>Martinen</PersonLastNm>
      </PersonFullName>
      <SSN>999009999</SSN>
    </SigningOfficerGrp>
    <IRSResponsiblePrtyInfoCurrInd>1</IRSResponsiblePrtyInfoCurrInd>
    <PreparerPersonGrp>
      <PreparerPersonNm>Francisco Contreras</PreparerPersonNm>
      <PTIN>P04924629</PTIN>
      <PhoneNum>6514924629</PhoneNum>
      <PreparationDt>2024-05-06</PreparationDt>
    </PreparerPersonGrp>
    <AdditionalFilerInformation>
      <TrustedCustomerGrp>
        <TrustedCustomerCd>0</TrustedCustomerCd>
        <OOBSecurityVerificationCd>11</OOBSecurityVerificationCd>
        <LastSubmissionRqrOOBCd>0</LastSubmissionRqrOOBCd>
        <AuthenticationAssuranceLevelCd>AAL2</AuthenticationAssuranceLevelCd>
      </TrustedCustomerGrp>
    </AdditionalFilerInformation>
    <TaxYr>2023</TaxYr>
    <BuildTS>2023-04-26 12:10:37Z</BuildTS>
  </ReturnHeader>
  <ReturnData documentCnt="2">
    <IRS990EZ documentId="R000001" referenceDocumentId="R000002" softwareId="23018249" softwareVersionNum="v1.00">
      <GroupExemptionNum>0264</GroupExemptionNum>
      <MethodOfAccountingCashInd>X</MethodOfAccountingCashInd>
      <ScheduleBNotRequiredInd>X</ScheduleBNotRequiredInd>
      <Organization501cInd organization501cTypeTxt="5">X</Organization501cInd>
      <TypeOfOrganizationOtherInd>X</TypeOfOrganizationOtherInd>
      <TypeOfOrganizationOtherDesc>Labor Union</TypeOfOrganizationOtherDesc>
      <GrossReceiptsAmt>61520</GrossReceiptsAmt>
      <InfoInScheduleOPartIInd>X</InfoInScheduleOPartIInd>
      <ContributionsGiftsGrantsEtcAmt>0</ContributionsGiftsGrantsEtcAmt>
      <ProgramServiceRevenueAmt>0</ProgramServiceRevenueAmt>
      <MembershipDuesAmt>13777</MembershipDuesAmt>
      <InvestmentIncomeAmt>39486</InvestmentIncomeAmt>
      <SaleOfAssetsGrossAmt>0</SaleOfAssetsGrossAmt>
      <CostOrOtherBasisExpenseSaleAmt>0</CostOrOtherBasisExpenseSaleAmt>
      <GainOrLossFromSaleOfAssetsAmt>0</GainOrLossFromSaleOfAssetsAmt>
      <GamingGrossIncomeAmt>0</GamingGrossIncomeAmt>
      <FundraisingGrossIncomeAmt fndrsngEventContriPrevRptAmt="0">0</FundraisingGrossIncomeAmt>
      <SpecialEventsDirectExpensesAmt>0</SpecialEventsDirectExpensesAmt>
      <SpecialEventsNetIncomeLossAmt>0</SpecialEventsNetIncomeLossAmt>
      <GrossSalesOfInventoryAmt>0</GrossSalesOfInventoryAmt>
      <CostOfGoodsSoldAmt>0</CostOfGoodsSoldAmt>
      <GrossProfitLossSlsOfInvntryAmt>0</GrossProfitLossSlsOfInvntryAmt>
      <OtherRevenueTotalAmt>8257</OtherRevenueTotalAmt>
      <TotalRevenueAmt>61520</TotalRevenueAmt>
      <GrantsAndSimilarAmountsPaidAmt>0</GrantsAndSimilarAmountsPaidAmt>
      <BenefitsPaidToOrForMembersAmt>0</BenefitsPaidToOrForMembersAmt>
      <SalariesOtherCompEmplBnftAmt>0</SalariesOtherCompEmplBnftAmt>
      <FeesAndOtherPymtToIndCntrctAmt>2760</FeesAndOtherPymtToIndCntrctAmt>
      <OccupancyRentUtltsAndMaintAmt>0</OccupancyRentUtltsAndMaintAmt>
      <PrintingPublicationsPostageAmt>2175</PrintingPublicationsPostageAmt>
      <OtherExpensesTotalAmt>21282</OtherExpensesTotalAmt>
      <TotalExpensesAmt>26217</TotalExpensesAmt>
      <ExcessOrDeficitForYearAmt>35303</ExcessOrDeficitForYearAmt>
      <NetAssetsOrFundBalancesBOYAmt>369477</NetAssetsOrFundBalancesBOYAmt>
      <OtherChangesInNetAssetsAmt>1394</OtherChangesInNetAssetsAmt>
      <NetAssetsOrFundBalancesEOYAmt>406174</NetAssetsOrFundBalancesEOYAmt>
      <InfoInScheduleOPartIIInd>X</InfoInScheduleOPartIIInd>
      <CashSavingsAndInvestmentsGrp>
        <BOYAmt>368714</BOYAmt>
        <EOYAmt>405665</EOYAmt>
      </CashSavingsAndInvestmentsGrp>
      <LandAndBuildingsGrp>
        <BOYAmt>0</BOYAmt>
        <EOYAmt>0</EOYAmt>
      </LandAndBuildingsGrp>
      <OtherAssetsTotalDetail>
        <BOYAmt>763</BOYAmt>
        <EOYAmt>509</EOYAmt>
      </OtherAssetsTotalDetail>
      <Form990TotalAssetsGrp>
        <BOYAmt>369477</BOYAmt>
        <EOYAmt>406174</EOYAmt>
      </Form990TotalAssetsGrp>
      <SumOfTotalLiabilitiesGrp>
        <BOYAmt>0</BOYAmt>
        <EOYAmt>0</EOYAmt>
      </SumOfTotalLiabilitiesGrp>
      <NetAssetsOrFundBalancesGrp>
        <BOYAmt>369477</BOYAmt>
        <EOYAmt>406174</EOYAmt>
      </NetAssetsOrFundBalancesGrp>
      <PrimaryExemptPurposeTxt>Working for the betterment of wages, hours and working conditions of represented members</PrimaryExemptPurposeTxt>
      <ProgramSrvcAccomplishmentGrp>
        <DescriptionProgramSrvcAccomTxt>Working for the betterment of wages, hours and working conditions of represented members</DescriptionProgramSrvcAccomTxt>
        <GrantsAndAllocationsAmt>0</GrantsAndAllocationsAmt>
        <ProgramServiceExpensesAmt>25964</ProgramServiceExpensesAmt>
      </ProgramSrvcAccomplishmentGrp>
      <TotalProgramServiceExpensesAmt>25964</TotalProgramServiceExpensesAmt>
      <OfficerDirectorTrusteeEmplGrp>
        <PersonNm>Lee Wentz</PersonNm>
        <TitleTxt>President</TitleTxt>
        <AverageHrsPerWkDevotedToPosRt>1</AverageHrsPerWkDevotedToPosRt>
        <CompensationAmt>0</CompensationAmt>
        <EmployeeBenefitProgramAmt>0</EmployeeBenefitProgramAmt>
        <ExpenseAccountOtherAllwncAmt>0</ExpenseAccountOtherAllwncAmt>
      </OfficerDirectorTrusteeEmplGrp>
      <OfficerDirectorTrusteeEmplGrp>
        <PersonNm>Jonah Baker</PersonNm>
        <TitleTxt>Recording Secretary</TitleTxt>
        <AverageHrsPerWkDevotedToPosRt>2</AverageHrsPerWkDevotedToPosRt>
        <CompensationAmt>0</CompensationAmt>
        <EmployeeBenefitProgramAmt>0</EmployeeBenefitProgramAmt>
        <ExpenseAccountOtherAllwncAmt>0</ExpenseAccountOtherAllwncAmt>
      </OfficerDirectorTrusteeEmplGrp>
      <OfficerDirectorTrusteeEmplGrp>
        <PersonNm>Brianne Martinen</PersonNm>
        <TitleTxt>Secretary treasurer</TitleTxt>
        <AverageHrsPerWkDevotedToPosRt>3</AverageHrsPerWkDevotedToPosRt>
        <CompensationAmt>0</CompensationAmt>
        <EmployeeBenefitProgramAmt>0</EmployeeBenefitProgramAmt>
        <ExpenseAccountOtherAllwncAmt>0</ExpenseAccountOtherAllwncAmt>
      </OfficerDirectorTrusteeEmplGrp>
      <OfficerDirectorTrusteeEmplGrp>
        <PersonNm>Boyd Hinton</PersonNm>
        <TitleTxt>Vice President</TitleTxt>
        <AverageHrsPerWkDevotedToPosRt>1</AverageHrsPerWkDevotedToPosRt>
        <CompensationAmt>0</CompensationAmt>
        <EmployeeBenefitProgramAmt>0</EmployeeBenefitProgramAmt>
        <ExpenseAccountOtherAllwncAmt>0</ExpenseAccountOtherAllwncAmt>
      </OfficerDirectorTrusteeEmplGrp>
      <OfficerDirectorTrusteeEmplGrp>
        <PersonNm>Tony Shimmin</PersonNm>
        <TitleTxt>Conductor Sentinel</TitleTxt>
        <AverageHrsPerWkDevotedToPosRt>1</AverageHrsPerWkDevotedToPosRt>
        <CompensationAmt>0</CompensationAmt>
        <EmployeeBenefitProgramAmt>0</EmployeeBenefitProgramAmt>
        <ExpenseAccountOtherAllwncAmt>0</ExpenseAccountOtherAllwncAmt>
      </OfficerDirectorTrusteeEmplGrp>
      <OfficerDirectorTrusteeEmplGrp>
        <PersonNm>Joshua Beede</PersonNm>
        <TitleTxt>Trustee</TitleTxt>
        <AverageHrsPerWkDevotedToPosRt>1</AverageHrsPerWkDevotedToPosRt>
        <CompensationAmt>0</CompensationAmt>
        <EmployeeBenefitProgramAmt>0</EmployeeBenefitProgramAmt>
        <ExpenseAccountOtherAllwncAmt>0</ExpenseAccountOtherAllwncAmt>
      </OfficerDirectorTrusteeEmplGrp>
      <OfficerDirectorTrusteeEmplGrp>
        <PersonNm>Melissa Parker</PersonNm>
        <TitleTxt>Trustee</TitleTxt>
        <AverageHrsPerWkDevotedToPosRt>1</AverageHrsPerWkDevotedToPosRt>
        <CompensationAmt>0</CompensationAmt>
        <EmployeeBenefitProgramAmt>0</EmployeeBenefitProgramAmt>
        <ExpenseAccountOtherAllwncAmt>0</ExpenseAccountOtherAllwncAmt>
      </OfficerDirectorTrusteeEmplGrp>
      <OfficerDirectorTrusteeEmplGrp>
        <PersonNm>Patricia Spencer</PersonNm>
        <TitleTxt>Trustee</TitleTxt>
        <AverageHrsPerWkDevotedToPosRt>1</AverageHrsPerWkDevotedToPosRt>
        <CompensationAmt>0</CompensationAmt>
        <EmployeeBenefitProgramAmt>0</EmployeeBenefitProgramAmt>
        <ExpenseAccountOtherAllwncAmt>0</ExpenseAccountOtherAllwncAmt>
      </OfficerDirectorTrusteeEmplGrp>
      <ActivitiesNotPreviouslyRptInd>0</ActivitiesNotPreviouslyRptInd>
      <ChgMadeToOrgnzngDocNotRptInd>0</ChgMadeToOrgnzngDocNotRptInd>
      <OrganizationHadUBIInd>0</OrganizationHadUBIInd>
      <SubjectToProxyTaxInd>0</SubjectToProxyTaxInd>
      <OrganizationDissolvedEtcInd>0</OrganizationDissolvedEtcInd>
      <DirectIndirectPltclExpendAmt>0</DirectIndirectPltclExpendAmt>
      <Form1120PolFiledInd>0</Form1120PolFiledInd>
      <MadeLoansToFromOfficersInd>0</MadeLoansToFromOfficersInd>
      <ProhibitedTaxShelterTransInd>0</ProhibitedTaxShelterTransInd>
      <BooksInCareOfDetail>
        <PersonNm>Brianne Martinen</PersonNm>
        <USAddress>
          <AddressLine1Txt>15 Hiltons Lane</AddressLine1Txt>
          <CityNm>Rochester</CityNm>
          <StateAbbreviationCd>NH</StateAbbreviationCd>
          <ZIPCd>03868</ZIPCd>
        </USAddress>
        <PhoneNum>6034220306</PhoneNum>
      </BooksInCareOfDetail>
      <ForeignFinancialAccountInd>0</ForeignFinancialAccountInd>
      <ForeignOfficeInd>0</ForeignOfficeInd>
      <DonorAdvisedFndsInd>0</DonorAdvisedFndsInd>
      <OperateHospitalInd>0</OperateHospitalInd>
      <TanningServicesProvidedInd>0</TanningServicesProvidedInd>
      <RelatedOrganizationCtrlEntInd>0</RelatedOrganizationCtrlEntInd>
      <TransactionWithControlEntInd>0</TransactionWithControlEntInd>
      <PoliticalCampaignActyInd>0</PoliticalCampaignActyInd>
    </IRS990EZ>
    <IRS990ScheduleO documentId="R000002" softwareId="23018249" softwareVersionNum="v1.00">
      <SupplementalInformationDetail>
        <FormAndLineReferenceDesc>Form 990-EZ, Part I, Line 8</FormAndLineReferenceDesc>
        <ExplanationTxt>Description;Amount^Reimbursements;6380|Redeposited and Proested Checks;529|New Member Incentives;1348^Total;8257^</ExplanationTxt>
      </SupplementalInformationDetail>
      <SupplementalInformationDetail>
        <FormAndLineReferenceDesc>Form 990-EZ, Part I, Line 16</FormAndLineReferenceDesc>
        <ExplanationTxt>Description;Amount^Reimbursed Expenses;18806|Bank Charges and Protested Checks;22|Donations;1200|Conferences conventions and meetings;1000|Depreciation;254^Total;21282^</ExplanationTxt>
      </SupplementalInformationDetail>
      <SupplementalInformationDetail>
        <FormAndLineReferenceDesc>Form 990-EZ, Part I, Line 20</FormAndLineReferenceDesc>
        <ExplanationTxt>This amount represents a loss on investments</ExplanationTxt>
      </SupplementalInformationDetail>
      <SupplementalInformationDetail>
        <FormAndLineReferenceDesc>Form 990-EZ, Part II, Line 24</FormAndLineReferenceDesc>
        <ExplanationTxt>This number represents fixed assets</ExplanationTxt>
      </SupplementalInformationDetail>
    </IRS990ScheduleO>
  </ReturnData>
</Return>
