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

    <documentType>4/A</documentType><periodOfReport>2003-08-06</periodOfReport><dateOfOriginalSubmission>2003-08-06</dateOfOriginalSubmission>
    <issuer>
        <issuerCik>0000028630</issuerCik>
        <issuerName>DRS TECHNOLOGIES INC</issuerName>
        <issuerTradingSymbol>DRS</issuerTradingSymbol></issuer><reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001053645</rptOwnerCik>
            <rptOwnerName>JAMES C SHELTON</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>310 EAST ROYAL PALM</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>BOCA RATON</rptOwnerCity>
            <rptOwnerState>FL</rptOwnerState>
            <rptOwnerZipCode>33432</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
            <reportingOwnerRelationship>
<isDirector>1</isDirector><isOfficer>0</isOfficer><isTenPercentOwner>0</isTenPercentOwner><isOther>0</isOther></reportingOwnerRelationship></reportingOwner><derivativeTable><derivativeTransaction><securityTitle><value>Stock Option (Right to Buy)</value></securityTitle><conversionOrExercisePrice><value>26.51</value><footnoteId id="F3"/></conversionOrExercisePrice><transactionDate><value>2003-08-06</value></transactionDate><transactionCoding><transactionFormType>4</transactionFormType><transactionCode>A</transactionCode><equitySwapInvolved>0</equitySwapInvolved></transactionCoding><transactionAmounts><transactionShares><value>2500</value></transactionShares><transactionPricePerShare><value>0</value><footnoteId id="F2"/></transactionPricePerShare><transactionAcquiredDisposedCode><value>A</value></transactionAcquiredDisposedCode></transactionAmounts><exerciseDate><value>2004-08-06</value></exerciseDate><expirationDate><value>2013-08-05</value></expirationDate><underlyingSecurity><underlyingSecurityTitle><value>Common Stock</value></underlyingSecurityTitle><underlyingSecurityShares><value>2500</value></underlyingSecurityShares></underlyingSecurity><postTransactionAmounts><sharesOwnedFollowingTransaction><value>0</value><footnoteId id="F1"/></sharesOwnedFollowingTransaction></postTransactionAmounts><ownershipNature><directOrIndirectOwnership><value>D</value></directOrIndirectOwnership><natureOfOwnership><value/></natureOfOwnership></ownershipNature></derivativeTransaction></derivativeTable><footnotes><footnote id="F1">Option to buy 2,500 shares granted August 6, 2003, exercisable as to 100% on August 6, 2004.</footnote><footnote id="F2">Option granted pursuant to stock option plan, for which no consideration was paid by recipient.</footnote><footnote id="F3">Amendment reflects correct exercise price.</footnote></footnotes><remarks/><ownerSignature><signatureName>C. Shelton James</signatureName><signatureDate>2003-08-12</signatureDate></ownerSignature></ownershipDocument>

