<SUBMISSION>
<ACCESSION-NUMBER>0000914190-03-000045
<TYPE>4
<PUBLIC-DOCUMENT-COUNT>1
<PERIOD>20030813
<FILING-DATE>20030813
<ISSUER>
<COMPANY-DATA>
<CONFORMED-NAME>SURMODICS INC
<CIK>0000924717
<ASSIGNED-SIC>2891
<IRS-NUMBER>411356149
<STATE-OF-INCORPORATION>MN
<FISCAL-YEAR-END>0930
</COMPANY-DATA>
<BUSINESS-ADDRESS>
<STREET1>9924 W 74TH ST
<CITY>EDEN PRAIRIE
<STATE>MN
<ZIP>55344
<PHONE>6128292700
</BUSINESS-ADDRESS>
<MAIL-ADDRESS>
<STREET1>9924 WEST 74TH ST
<CITY>EDEN PRAIRIE
<STATE>MN
<ZIP>55344
</MAIL-ADDRESS>
<FORMER-COMPANY>
<FORMER-CONFORMED-NAME>BSI CORP
<DATE-CHANGED>19970506
</FORMER-COMPANY>
</ISSUER>
<REPORTING-OWNER>
<OWNER-DATA>
<CONFORMED-NAME>KELLER KENNETH H
<CIK>0001182833
</OWNER-DATA>
<FILING-VALUES>
<FORM-TYPE>4
<ACT>34
<FILE-NUMBER>000-23837
<FILM-NUMBER>03841013
</FILING-VALUES>
<BUSINESS-ADDRESS>
<STREET1>C/O SURMODIES INC
<STREET2>9924 WEST 74TH ST
<CITY>EDEN PRIRIE
<STATE>MN
<ZIP>55344
<PHONE>9528292700
</BUSINESS-ADDRESS>
<MAIL-ADDRESS>
<STREET1>C/O SURMODIES INC
<STREET2>9924 WEST 74TH ST
<CITY>EDEN PRAIRIE
<STATE>MN
<ZIP>55344
</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>2003-08-13</periodOfReport>
    <issuer>
        <issuerCik>0000924717</issuerCik>
        <issuerName>SURMODICS INC</issuerName>
        <issuerTradingSymbol>SRDX</issuerTradingSymbol></issuer><reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001182833</rptOwnerCik>
            <rptOwnerName>KELLER KENNETH H</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>6182 CRACKLEBERRY TRAIL</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>WOODBURY</rptOwnerCity>
            <rptOwnerState>MN</rptOwnerState>
            <rptOwnerZipCode>55129</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
            <reportingOwnerRelationship>
<isDirector>1</isDirector><isOfficer>0</isOfficer><isTenPercentOwner>0</isTenPercentOwner><isOther>0</isOther></reportingOwnerRelationship></reportingOwner><nonDerivativeTable><nonDerivativeTransaction><securityTitle><value>Common Stock</value></securityTitle><transactionDate><value>2003-08-13</value></transactionDate><transactionCoding><transactionFormType>4</transactionFormType><transactionCode>S</transactionCode><equitySwapInvolved>0</equitySwapInvolved></transactionCoding><transactionAmounts><transactionShares><value>2000</value></transactionShares><transactionPricePerShare><value>34.24</value><footnoteId id="F1"/></transactionPricePerShare><transactionAcquiredDisposedCode><value>D</value></transactionAcquiredDisposedCode></transactionAmounts><postTransactionAmounts><sharesOwnedFollowingTransaction><value>6800</value></sharesOwnedFollowingTransaction></postTransactionAmounts><ownershipNature><directOrIndirectOwnership><value>D</value></directOrIndirectOwnership><natureOfOwnership><value/></natureOfOwnership></ownershipNature></nonDerivativeTransaction></nonDerivativeTable><derivativeTable><derivativeHolding><securityTitle><value>Director Stock Option (Right to Buy)</value></securityTitle><conversionOrExercisePrice><value>2.50</value></conversionOrExercisePrice><exerciseDate><value>1997-10-01</value><footnoteId id="F2"/></exerciseDate><expirationDate><value>2007-10-01</value></expirationDate><underlyingSecurity><underlyingSecurityTitle><value>Common Stock</value></underlyingSecurityTitle><underlyingSecurityShares><value>24000</value></underlyingSecurityShares></underlyingSecurity><postTransactionAmounts><sharesOwnedFollowingTransaction><value>24000</value></sharesOwnedFollowingTransaction></postTransactionAmounts><ownershipNature><directOrIndirectOwnership><value>D</value></directOrIndirectOwnership><natureOfOwnership><value/></natureOfOwnership></ownershipNature></derivativeHolding></derivativeTable><footnotes><footnote id="F1">200 of the 2,000 shares were sold at a price of $34.19 per share</footnote><footnote id="F2">Exercisable in annual increments of 5,600 shares each, commencing 10/1/97</footnote></footnotes><remarks/><ownerSignature><signatureName>Kenneth H. Keller</signatureName><signatureDate>2003-08-13</signatureDate></ownerSignature></ownershipDocument>

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