<SUBMISSION>
<ACCESSION-NUMBER>0001238550-04-000014
<TYPE>4
<PUBLIC-DOCUMENT-COUNT>1
<PERIOD>20040331
<FILING-DATE>20040402
<ISSUER>
<COMPANY-DATA>
<CONFORMED-NAME>DREW INDUSTRIES INC
<CIK>0000763744
<ASSIGNED-SIC>3442
<IRS-NUMBER>133250533
<STATE-OF-INCORPORATION>DE
<FISCAL-YEAR-END>1231
</COMPANY-DATA>
<BUSINESS-ADDRESS>
<STREET1>200 MAMARONECK AVE
<CITY>WHITE PLAINS
<STATE>NY
<ZIP>10601
<PHONE>9144289098
</BUSINESS-ADDRESS>
<MAIL-ADDRESS>
<STREET1>200 MAMARONECK AVE
<CITY>WHITE PLAINS
<STATE>NY
<ZIP>10601
</MAIL-ADDRESS>
</ISSUER>
<REPORTING-OWNER>
<OWNER-DATA>
<CONFORMED-NAME>WEBSTER DAVID
<CIK>0001238363
</OWNER-DATA>
<FILING-VALUES>
<FORM-TYPE>4
<ACT>34
<FILE-NUMBER>001-13646
<FILM-NUMBER>04711896
</FILING-VALUES>
<MAIL-ADDRESS>
<STREET1>C/O KINRO INC
<STREET2>4381 GREEN OAKS BLVD WEST STE 200
<CITY>ARLINGTON
<STATE>TX
<ZIP>76106
</MAIL-ADDRESS>
</REPORTING-OWNER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>edgar.xml
<DESCRIPTION>PRIMARY DOCUMENT
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0201</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2004-03-31</periodOfReport>

    <issuer>
        <issuerCik>0000763744</issuerCik>
        <issuerName>DREW INDUSTRIES INC</issuerName>
        <issuerTradingSymbol>DW</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001238363</rptOwnerCik>
            <rptOwnerName>WEBSTER DAVID</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O KINRO, INC.</rptOwnerStreet1>
            <rptOwnerStreet2>4381 GREEN OAKS BOULEVARD WEST</rptOwnerStreet2>
            <rptOwnerCity>ARLINGTON</rptOwnerCity>
            <rptOwnerState>TX</rptOwnerState>
            <rptOwnerZipCode>76016</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>1</isOther>
            <otherText>CEO &amp; President of Subsidiary</otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2004-03-31</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>S</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>8963</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>35.9083</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>148877</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value></value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <footnotes></footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>Fredric M. Zinn, on behalf of David L. Webster</signatureName>
        <signatureDate>2004-04-01</signatureDate>
    </ownerSignature>
</ownershipDocument>

</XML>
</TEXT>
</DOCUMENT>
</SUBMISSION>
