<SUBMISSION>
<ACCESSION-NUMBER>0000920371-03-000053
<TYPE>4
<PUBLIC-DOCUMENT-COUNT>1
<PERIOD>20030909
<FILING-DATE>20030911
<REPORTING-OWNER>
<OWNER-DATA>
<CONFORMED-NAME>TOWNSEND DONALD M
<CIK>0001036046
</OWNER-DATA>
<FILING-VALUES>
<FORM-TYPE>4
<ACT>34
<FILE-NUMBER>001-13429
<FILM-NUMBER>03891550
</FILING-VALUES>
<BUSINESS-ADDRESS>
<STREET1>4120 DUBLIN BOULEVARD
<STREET2>SUITE 400
<CITY>DUBLIN
<STATE>CA
<ZIP>94568
</BUSINESS-ADDRESS>
<MAIL-ADDRESS>
<STREET1>4120 DUBLIN BOULEVARD
<STREET2>SUITE 400
<CITY>DUBLIN
<STATE>CA
<ZIP>94568
</MAIL-ADDRESS>
<FORMER-NAME>
<FORMER-CONFORMED-NAME>TOWSEND DONALD M
<DATE-CHANGED>19970319
</FORMER-NAME>
</REPORTING-OWNER>
<ISSUER>
<COMPANY-DATA>
<CONFORMED-NAME>SIMPSON MANUFACTURING CO INC /CA/
<CIK>0000920371
<ASSIGNED-SIC>3420
<IRS-NUMBER>943196943
<STATE-OF-INCORPORATION>DE
<FISCAL-YEAR-END>1231
</COMPANY-DATA>
<BUSINESS-ADDRESS>
<STREET1>4120 DUBLILN BLVD STE 400
<CITY>DUBLIN
<STATE>CA
<ZIP>94568
<PHONE>9255609000
</BUSINESS-ADDRESS>
<MAIL-ADDRESS>
<STREET1>4120 DUBLIN BLVD STE 400
<CITY>DUBLIN
<STATE>CA
<ZIP>94568
</MAIL-ADDRESS>
</ISSUER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>edgar.xml
<DESCRIPTION>PRIMARY DOCUMENT
<TEXT>
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<?xml version="1.0"?>
<ownershipDocument>
    <schemaVersion>X0201</schemaVersion>

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        <issuerName>SIMPSON MANUFACTURING CO INC /CA/</issuerName>
        <issuerTradingSymbol>NYSE:SSD</issuerTradingSymbol></issuer><reportingOwner>
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            <rptOwnerCik>0001036046</rptOwnerCik>
            <rptOwnerName>TOWNSEND DONALD M</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
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            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>DUBLIN</rptOwnerCity>
            <rptOwnerState>CA</rptOwnerState>
            <rptOwnerZipCode>94568</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
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            <reportingOwnerRelationship>
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This option vests equally over four years beginning with the date of grant.</footnote></footnotes><remarks/><ownerSignature><signatureName>/s/DONALD M. TOWNSEND</signatureName><signatureDate>2003-09-11</signatureDate></ownerSignature></ownershipDocument>

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