<?xml version="1.0"?>
<ownershipDocument>
    <schemaVersion>X0101</schemaVersion>

    <documentType>4</documentType><periodOfReport>2003-05-15</periodOfReport>
    <issuer>
        <issuerCik>0000779164</issuerCik>
        <issuerName>PROTERION CORP</issuerName>
        <issuerTradingSymbol>PRC</issuerTradingSymbol></issuer><reportingOwner><reportingOwnerId>
            <rptOwnerCik>0001241686</rptOwnerCik>
            <rptOwnerName>WOITACH PAUL</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>  </rptOwnerStreet1>
            <rptOwnerStreet2>  </rptOwnerStreet2>
            <rptOwnerCity>  </rptOwnerCity>
            <rptOwnerState>  </rptOwnerState>
            <rptOwnerZipCode>  </rptOwnerZipCode>
        </reportingOwnerAddress>
            <reportingOwnerRelationship>
<isDirector>1</isDirector><isOfficer>0</isOfficer><isTenPercentOwner>0</isTenPercentOwner><isOther>0</isOther></reportingOwnerRelationship></reportingOwner><derivativeSecurity><securityTitle><value>Option (right to buy)</value><footnoteId id="F1"/></securityTitle><conversionOrExercisePrice><value>.31</value></conversionOrExercisePrice><transactionDate><value>2003-05-15</value></transactionDate><transactionCoding><transactionFormType>4</transactionFormType><transactionCode>A</transactionCode><equitySwapInvolved>0</equitySwapInvolved></transactionCoding><transactionAmounts><transactionShares><value>40000</value></transactionShares><transactionValue><value>0</value></transactionValue><transactionAcquiredDisposedCode><value>A</value></transactionAcquiredDisposedCode></transactionAmounts><exerciseDate><value>2003-11-15</value><footnoteId id="F2"/></exerciseDate><expirationDate><value>2013-05-15</value></expirationDate><underlyingSecurity><underlyingSecurityTitle><value>Common Stock</value></underlyingSecurityTitle><underlyingSecurityShares><value>40000</value></underlyingSecurityShares></underlyingSecurity><postTransactionAmounts><sharesOwnedFollowingTransaction><value>40000</value></sharesOwnedFollowingTransaction></postTransactionAmounts><ownershipNature><directOrIndirectOwnership><value>D</value></directOrIndirectOwnership><natureOfOwnership><value/></natureOfOwnership></ownershipNature></derivativeSecurity><footnotes><footnote id="F1">Option to purchase shares under the Company's 2003 Equity Incentive Plan.</footnote><footnote id="F2">The option vests in twelve equal monthly installments beginning on June 18, 2003, however, the vested portion is not first exercisable until six months after May 15, 2003.</footnote></footnotes><ownerSignature><signatureName>PAUL WOITACH</signatureName><signatureDate>2003-07-15</signatureDate></ownerSignature></ownershipDocument>

