<?xml version="1.0"?>
<ownershipDocument>
    <schemaVersion>X0201</schemaVersion>

    <documentType>4</documentType><periodOfReport>2003-11-04</periodOfReport><notSubjectToSection16>1</notSubjectToSection16>
    <issuer>
        <issuerCik>0000920354</issuerCik>
        <issuerName>MRO SOFTWARE INC</issuerName>
        <issuerTradingSymbol>MROI</issuerTradingSymbol></issuer><reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0000948839</rptOwnerCik>
            <rptOwnerName>DANIELS ROBERT L</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O MRO SOFTWARE, INC.</rptOwnerStreet1>
            <rptOwnerStreet2>100 CROSBY DRIVE</rptOwnerStreet2>
            <rptOwnerCity>BEDFORD</rptOwnerCity>
            <rptOwnerState>MA</rptOwnerState>
            <rptOwnerZipCode>01730</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
            <reportingOwnerRelationship>
<isDirector>1</isDirector><isOfficer>0</isOfficer><isTenPercentOwner>1</isTenPercentOwner><isOther>0</isOther></reportingOwnerRelationship></reportingOwner><derivativeTable><derivativeTransaction><securityTitle><value>Employee Stock Option</value></securityTitle><conversionOrExercisePrice><value>13.89</value></conversionOrExercisePrice><transactionDate><value>2003-11-21</value></transactionDate><transactionCoding><transactionFormType>4</transactionFormType><transactionCode>A</transactionCode><equitySwapInvolved>0</equitySwapInvolved></transactionCoding><transactionAmounts><transactionShares><value>15262</value></transactionShares><transactionPricePerShare><footnoteId id="F1"/></transactionPricePerShare><transactionAcquiredDisposedCode><value>A</value></transactionAcquiredDisposedCode></transactionAmounts><exerciseDate><footnoteId id="F1"/></exerciseDate><expirationDate><value>2013-11-04</value></expirationDate><underlyingSecurity><underlyingSecurityTitle><value>Common Stock, $ .01 Par Value</value></underlyingSecurityTitle><underlyingSecurityShares><value>15262</value></underlyingSecurityShares></underlyingSecurity><postTransactionAmounts><sharesOwnedFollowingTransaction><value>15262</value></sharesOwnedFollowingTransaction></postTransactionAmounts><ownershipNature><directOrIndirectOwnership><value>D</value></directOrIndirectOwnership><natureOfOwnership><value/></natureOfOwnership></ownershipNature></derivativeTransaction></derivativeTable><footnotes><footnote id="F1">Option granted under Issuer's Amended and Restated 1999 Equity Incentive Plan, vesting over four years term commencing November 3, 2003, with 25% of the shares vesting on November 3, 2004, and thereafter in 36 equal monthly installments.</footnote></footnotes><remarks/><ownerSignature><signatureName>Robert L. Daniels</signatureName><signatureDate>2003-11-25</signatureDate></ownerSignature></ownershipDocument>

