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

    <documentType>4</documentType><periodOfReport>2003-08-27</periodOfReport>
    <issuer>
        <issuerCik>0001054374</issuerCik>
        <issuerName>BROADCOM CORP</issuerName>
        <issuerTradingSymbol>BRCM</issuerTradingSymbol></issuer><reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001201633</rptOwnerCik>
            <rptOwnerName>SAMUELI HENRY</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>16215 ALTON PARKWAY</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>IRVINE</rptOwnerCity>
            <rptOwnerState>CA</rptOwnerState>
            <rptOwnerZipCode>92618</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
            <reportingOwnerRelationship>
<isDirector>1</isDirector><isOfficer>1</isOfficer><isTenPercentOwner>1</isTenPercentOwner><isOther>0</isOther><officerTitle>Chairman of the Board and CTO</officerTitle></reportingOwnerRelationship></reportingOwner><nonDerivativeTable><nonDerivativeTransaction><securityTitle><value>Class A common stock</value><footnoteId id="F1"/></securityTitle><transactionDate><value>2003-08-27</value></transactionDate><transactionCoding><transactionFormType>4</transactionFormType><transactionCode>C</transactionCode><equitySwapInvolved>0</equitySwapInvolved></transactionCoding><transactionAmounts><transactionShares><value>162500</value></transactionShares><transactionPricePerShare><footnoteId id="F2"/></transactionPricePerShare><transactionAcquiredDisposedCode><value>A</value></transactionAcquiredDisposedCode></transactionAmounts><postTransactionAmounts><sharesOwnedFollowingTransaction><value>162500</value></sharesOwnedFollowingTransaction></postTransactionAmounts><ownershipNature><directOrIndirectOwnership><value>I</value></directOrIndirectOwnership><natureOfOwnership><value>See Footnote</value><footnoteId id="F3"/></natureOfOwnership></ownershipNature></nonDerivativeTransaction><nonDerivativeTransaction><securityTitle><value>Class A common stock</value><footnoteId id="F1"/></securityTitle><transactionDate><value>2003-08-27</value></transactionDate><transactionCoding><transactionFormType>4</transactionFormType><transactionCode>S</transactionCode><equitySwapInvolved>0</equitySwapInvolved></transactionCoding><transactionAmounts><transactionShares><value>162500</value></transactionShares><transactionPricePerShare><value>25.7693</value></transactionPricePerShare><transactionAcquiredDisposedCode><value>D</value></transactionAcquiredDisposedCode></transactionAmounts><postTransactionAmounts><sharesOwnedFollowingTransaction><value>0</value></sharesOwnedFollowingTransaction></postTransactionAmounts><ownershipNature><directOrIndirectOwnership><value>I</value></directOrIndirectOwnership><natureOfOwnership><value>See Footnote</value><footnoteId id="F1"/></natureOfOwnership></ownershipNature></nonDerivativeTransaction><nonDerivativeHolding><securityTitle><value>Class A common stock</value></securityTitle><postTransactionAmounts><sharesOwnedFollowingTransaction><value>4</value></sharesOwnedFollowingTransaction></postTransactionAmounts><ownershipNature><directOrIndirectOwnership><value>D</value></directOrIndirectOwnership><natureOfOwnership><value/></natureOfOwnership></ownershipNature></nonDerivativeHolding></nonDerivativeTable><derivativeTable><derivativeTransaction><securityTitle><value>Class B common stock</value><footnoteId id="F1"/></securityTitle><conversionOrExercisePrice><footnoteId id="F2"/></conversionOrExercisePrice><transactionDate><value>2003-08-27</value></transactionDate><transactionCoding><transactionFormType>4</transactionFormType><transactionCode>C</transactionCode><equitySwapInvolved>0</equitySwapInvolved></transactionCoding><transactionAmounts><transactionShares><value>162500</value></transactionShares><transactionPricePerShare><value>0</value></transactionPricePerShare><transactionAcquiredDisposedCode><value>D</value></transactionAcquiredDisposedCode></transactionAmounts><exerciseDate><footnoteId id="F2"/></exerciseDate><expirationDate><footnoteId id="F2"/></expirationDate><underlyingSecurity><underlyingSecurityTitle><value>Class A common stock</value></underlyingSecurityTitle><underlyingSecurityShares><value>162500</value></underlyingSecurityShares></underlyingSecurity><postTransactionAmounts><sharesOwnedFollowingTransaction><value>2096149</value></sharesOwnedFollowingTransaction></postTransactionAmounts><ownershipNature><directOrIndirectOwnership><value>I</value></directOrIndirectOwnership><natureOfOwnership><value>See Footnote</value><footnoteId id="F3"/></natureOfOwnership></ownershipNature></derivativeTransaction><derivativeHolding><securityTitle><value>Class B common stock</value></securityTitle><conversionOrExercisePrice><footnoteId id="F2"/></conversionOrExercisePrice><exerciseDate><footnoteId id="F2"/></exerciseDate><expirationDate><footnoteId id="F2"/></expirationDate><underlyingSecurity><underlyingSecurityTitle><value>Class A common stock</value></underlyingSecurityTitle><underlyingSecurityShares><value>6588418</value></underlyingSecurityShares></underlyingSecurity><postTransactionAmounts><sharesOwnedFollowingTransaction><value>6588418</value></sharesOwnedFollowingTransaction></postTransactionAmounts><ownershipNature><directOrIndirectOwnership><value>I</value></directOrIndirectOwnership><natureOfOwnership><value>See Footnote</value><footnoteId id="F4"/></natureOfOwnership></ownershipNature></derivativeHolding><derivativeHolding><securityTitle><value>Class B common stock</value></securityTitle><conversionOrExercisePrice><footnoteId id="F2"/></conversionOrExercisePrice><exerciseDate><footnoteId id="F2"/></exerciseDate><expirationDate><footnoteId id="F2"/></expirationDate><underlyingSecurity><underlyingSecurityTitle><value>Class A common stock</value></underlyingSecurityTitle><underlyingSecurityShares><value>17139135</value></underlyingSecurityShares></underlyingSecurity><postTransactionAmounts><sharesOwnedFollowingTransaction><value>17139135</value></sharesOwnedFollowingTransaction></postTransactionAmounts><ownershipNature><directOrIndirectOwnership><value>I</value></directOrIndirectOwnership><natureOfOwnership><value>See Footnote</value><footnoteId id="F5"/></natureOfOwnership></ownershipNature></derivativeHolding><derivativeHolding><securityTitle><value>Class B common stock</value></securityTitle><conversionOrExercisePrice><footnoteId id="F2"/></conversionOrExercisePrice><exerciseDate><footnoteId id="F2"/></exerciseDate><expirationDate><footnoteId id="F2"/></expirationDate><underlyingSecurity><underlyingSecurityTitle><value>Class A common stock</value></underlyingSecurityTitle><underlyingSecurityShares><value>3675000</value></underlyingSecurityShares></underlyingSecurity><postTransactionAmounts><sharesOwnedFollowingTransaction><value>3675000</value></sharesOwnedFollowingTransaction></postTransactionAmounts><ownershipNature><directOrIndirectOwnership><value>I</value></directOrIndirectOwnership><natureOfOwnership><value>See Footnote</value><footnoteId id="F6"/></natureOfOwnership></ownershipNature></derivativeHolding><derivativeHolding><securityTitle><value>Class B common stock</value></securityTitle><conversionOrExercisePrice><footnoteId id="F2"/></conversionOrExercisePrice><exerciseDate><footnoteId id="F2"/></exerciseDate><expirationDate><footnoteId id="F2"/></expirationDate><underlyingSecurity><underlyingSecurityTitle><value>Class A common stock</value></underlyingSecurityTitle><underlyingSecurityShares><value>860865</value></underlyingSecurityShares></underlyingSecurity><postTransactionAmounts><sharesOwnedFollowingTransaction><value>860865</value></sharesOwnedFollowingTransaction></postTransactionAmounts><ownershipNature><directOrIndirectOwnership><value>I</value></directOrIndirectOwnership><natureOfOwnership><value>See Footnote</value><footnoteId id="F7"/></natureOfOwnership></ownershipNature></derivativeHolding></derivativeTable><footnotes><footnote id="F1">Such transaction was effected by HS Management, L.P.  The reporting person may be deemed to beneficially own the issuer's securities held by HS Management L.P. The reporting person disclaims beneficial ownership of these securities except to the extent of his pecuniary interest therein.</footnote><footnote id="F2">Each share of Class B Common Stock is convertible at any time into one share of Class A Common Stock at the option of the holder.</footnote><footnote id="F3">Held by HS Management, L.P.  The reporting person may be deemed to beneficially own the issuer's securities held by HS Management L.P. The reporting person disclaims beneficial ownership of these securities except to the extent of his pecuniary interest therein.</footnote><footnote id="F4">Held by the Shiloh Trust (the amended name of the Samueli Family Trust, effective 10/25/2000).  The reporting person, as co-trustee and co-beneficiary of such trust, is deemed to beneficially own the issuer's securities held by such trust.  The reporting person disclaims beneficial ownership of these securities except to the extent of his pecuniary interest therein.</footnote><footnote id="F5">Held by HS Portfolio L.P.  The reporting person may be deemed to beneficially own the issuer's securities held by HS Portfolio L.P. The reporting person disclaims beneficial ownership of these securities except to the extent of his pecuniary interest therein.</footnote><footnote id="F6">Held by The Henry Samueli Lifetime Benefit Trust.  The reporting person beneficially owns the issuer's securities held by The Henry Samueli Lifetime Benefit Trust.</footnote><footnote id="F7">Held by H&amp;S Investments I L.P., an entity owned by the Shiloh Trust. Accordingly, the reporting person is deemed to beneficially own the issuer's securities held by H&amp;S Investments I L.P.  The reporting person disclaims beneficial ownership of these securities except to the extent of his pecuniary interest therein.</footnote></footnotes><remarks/><ownerSignature><signatureName>Henry Samueli</signatureName><signatureDate>2003-08-27</signatureDate></ownerSignature></ownershipDocument>

