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

    <documentType>3</documentType><periodOfReport>2003-12-22</periodOfReport>
    <noSecuritiesOwned>0</noSecuritiesOwned>

    <issuer>
        <issuerCik>0001104332</issuerCik>
        <issuerName>SUMMUS INC USA</issuerName>
        <issuerTradingSymbol>SUMU</issuerTradingSymbol></issuer><reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001274432</rptOwnerCik>
            <rptOwnerName>HUGHES J WINDER</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>434 FAYETTEVILLE STREET, SUITE 600</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>RALEIGH</rptOwnerCity>
            <rptOwnerState>NC</rptOwnerState>
            <rptOwnerZipCode>27601</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
            <reportingOwnerRelationship>
<isDirector>1</isDirector><isOfficer>0</isOfficer><isTenPercentOwner>0</isTenPercentOwner><isOther>0</isOther></reportingOwnerRelationship></reportingOwner><nonDerivativeTable><nonDerivativeHolding><securityTitle><value>Common Stock</value></securityTitle><postTransactionAmounts><sharesOwnedFollowingTransaction><value>100000</value></sharesOwnedFollowingTransaction></postTransactionAmounts><ownershipNature><directOrIndirectOwnership><value>I</value></directOrIndirectOwnership><natureOfOwnership><value>see foonote </value><footnoteId id="F2"/></natureOfOwnership></ownershipNature></nonDerivativeHolding></nonDerivativeTable><derivativeTable><derivativeHolding><securityTitle><value>Series D Convertible Preferred Stock</value></securityTitle><conversionOrExercisePrice><footnoteId id="F1"/></conversionOrExercisePrice><exerciseDate><footnoteId id="F1"/></exerciseDate><expirationDate><footnoteId id="F1"/></expirationDate><underlyingSecurity><underlyingSecurityTitle><value>Common Stock</value></underlyingSecurityTitle><underlyingSecurityShares><value>1500000</value></underlyingSecurityShares></underlyingSecurity><ownershipNature><directOrIndirectOwnership><value>I</value></directOrIndirectOwnership><natureOfOwnership><value>See Footnote </value><footnoteId id="F2"/></natureOfOwnership></ownershipNature></derivativeHolding><derivativeHolding><securityTitle><value>Warrants (Option to Purchase)</value></securityTitle><conversionOrExercisePrice><value>.35</value></conversionOrExercisePrice><exerciseDate><value>2003-09-26</value></exerciseDate><expirationDate><value>2008-09-26</value></expirationDate><underlyingSecurity><underlyingSecurityTitle><value>Common Stock</value></underlyingSecurityTitle><underlyingSecurityShares><value>750000</value></underlyingSecurityShares></underlyingSecurity><ownershipNature><directOrIndirectOwnership><value>I</value></directOrIndirectOwnership><natureOfOwnership><value>See Footnote </value><footnoteId id="F2"/></natureOfOwnership></ownershipNature></derivativeHolding><derivativeHolding><securityTitle><value>Warrants (Option to Purchase)</value></securityTitle><conversionOrExercisePrice><value>.35</value></conversionOrExercisePrice><exerciseDate><value>2003-10-03</value></exerciseDate><expirationDate><value>2006-10-03</value></expirationDate><underlyingSecurity><underlyingSecurityTitle><value>Common Stock</value></underlyingSecurityTitle><underlyingSecurityShares><value>800000</value></underlyingSecurityShares></underlyingSecurity><ownershipNature><directOrIndirectOwnership><value>D</value></directOrIndirectOwnership><natureOfOwnership><value/></natureOfOwnership></ownershipNature></derivativeHolding><derivativeHolding><securityTitle><value>Options (Option to Purchase)</value></securityTitle><conversionOrExercisePrice><value>.19</value></conversionOrExercisePrice><exerciseDate><value>2003-12-22</value></exerciseDate><expirationDate><value>2013-12-22</value></expirationDate><underlyingSecurity><underlyingSecurityTitle><value>Common Stock</value></underlyingSecurityTitle><underlyingSecurityShares><value>11095</value><footnoteId id="F3"/></underlyingSecurityShares></underlyingSecurity><ownershipNature><directOrIndirectOwnership><value>D</value></directOrIndirectOwnership><natureOfOwnership><value/></natureOfOwnership></ownershipNature></derivativeHolding><derivativeHolding><securityTitle><value>Options (Option to Purchase)</value></securityTitle><conversionOrExercisePrice><value>.19</value></conversionOrExercisePrice><exerciseDate><value>2003-12-22</value></exerciseDate><expirationDate><value>2013-12-22</value></expirationDate><underlyingSecurity><underlyingSecurityTitle><value>Common Stock</value></underlyingSecurityTitle><underlyingSecurityShares><value>30000</value><footnoteId id="F4"/></underlyingSecurityShares></underlyingSecurity><ownershipNature><directOrIndirectOwnership><value>D</value></directOrIndirectOwnership><natureOfOwnership><value/></natureOfOwnership></ownershipNature></derivativeHolding></derivativeTable><footnotes><footnote id="F1">N/A</footnote><footnote id="F2">Owned by the Focus Fund L.P., of which Mr. Hughes is the general partner and chief investment officer.</footnote><footnote id="F3">These options were granted to Mr. Hughes under the Company's 2000 Amended and Restated Stock Option Plan.  1,095 of these options vest on January 1, 2004 and the remaining 10,000 vest on April 1, 2004.</footnote><footnote id="F4">These options were granted to Mr. Hughes under the Company's 2000 Amended and Restated Stock Option Plan.  7,500 of these options vest quarterly from the date of grant.</footnote></footnotes><remarks/><ownerSignature><signatureName>Donald T. Locke, Attorney-in-Fact</signatureName><signatureDate>2003-12-30</signatureDate></ownerSignature></ownershipDocument>

