<SUBMISSION>
<ACCESSION-NUMBER>0001111928-08-000048
<TYPE>4
<PUBLIC-DOCUMENT-COUNT>1
<PERIOD>20080506
<FILING-DATE>20080508
<DATE-OF-FILING-DATE-CHANGE>20080508
<REPORTING-OWNER>
<OWNER-DATA>
<CONFORMED-NAME>Shcherbakov Eugene A
<CIK>0001378544
</OWNER-DATA>
<FILING-VALUES>
<FORM-TYPE>4
<ACT>34
<FILE-NUMBER>001-33155
<FILM-NUMBER>08814071
</FILING-VALUES>
<BUSINESS-ADDRESS>
<PHONE>508-373-1100
</BUSINESS-ADDRESS>
<MAIL-ADDRESS>
<STREET1>IPG PHOTONICS CORPORATION
<STREET2>50 OLD WEBSTER ROAD
<CITY>OXFORD
<STATE>MA
<ZIP>01540
</MAIL-ADDRESS>
</REPORTING-OWNER>
<ISSUER>
<COMPANY-DATA>
<CONFORMED-NAME>IPG PHOTONICS CORP
<CIK>0001111928
<ASSIGNED-SIC>3674
<IRS-NUMBER>043444218
<STATE-OF-INCORPORATION>DE
</COMPANY-DATA>
<BUSINESS-ADDRESS>
<STREET1>50 OLD WEBSTER ROAD
<CITY>OXFORD
<STATE>MA
<ZIP>01540
<PHONE>5083731100
</BUSINESS-ADDRESS>
<MAIL-ADDRESS>
<STREET1>50 OLD WEBSTER ROAD
<CITY>OXFORD
<STATE>MA
<ZIP>01540
</MAIL-ADDRESS>
</ISSUER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>edgar.xml
<DESCRIPTION>PRIMARY DOCUMENT
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0202</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2008-05-06</periodOfReport>

    <issuer>
        <issuerCik>0001111928</issuerCik>
        <issuerName>IPG PHOTONICS CORP</issuerName>
        <issuerTradingSymbol>IPGP</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001378544</rptOwnerCik>
            <rptOwnerName>Shcherbakov Eugene A</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O IPG PHOTONICS CORPORATION</rptOwnerStreet1>
            <rptOwnerStreet2>50 OLD WEBSTER ROAD</rptOwnerStreet2>
            <rptOwnerCity>OXFORD</rptOwnerCity>
            <rptOwnerState>MA</rptOwnerState>
            <rptOwnerZipCode>01540</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>Managing Director of IPG Laser</officerTitle>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2008-05-06</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>S</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
                <footnoteId id="F1"/>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>150000</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>18.17</value>
                    <footnoteId id="F2"/>
                    <footnoteId id="F3"/>
                    <footnoteId id="F4"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>39994</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value></value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <footnotes>
        <footnote id="F1">The sales reported in this Form 4 were effected pursuant to a Rule 10b5-1 trading plan adopted by the reporting person on March 14, 2008.</footnote>
        <footnote id="F2">Sales ranged from $17.50 to $19.06 as follows:  19,177 shares at $17.50; 100 shares at $17.51; 1,600 shares at $17.51; 2,100 shares at $17.52; 100 shares at $17.53; 300 shares at $17.53; 300 shares at $17.54; 100 shares at $17.54; 100 shares at $17.54; 490 shares at $17.54; 100 shares at $17.55; 1,568 shares at $17.55; 200 shares at $17.56; 2,199 shares at $17.57; 2,400 shares at $17.58; 1,500 shares at $17.59; 100 shares at $17.59; 1,500 shares at $17.60; 1,200 shares at $17.61; 1,200 shares at $17.62; 300 shares at $17.64; 1,800 shares at $17.65; 2,700 shares at $17.66; 17 shares at $17.67; 300 shares at $17.69; 124 shares at $17.71; 400 shares at $17.73; 1,542 shares at $17.74; 283 shares at $17.83; 100 shares at $17.87; 1,100 shares at $17.91; 500 shares at $17.96; 4,200 shares at $17.97; 200 shares at $17.98; 100 shares at $17.99; 9,600 shares at $18.00; 600 shares at $18.03; 2,500 shares at $18.04; 200 shares at $18.05; 600 shares at $18.06; Cont. in footnote 3.</footnote>
        <footnote id="F3">900 shares at $18.07; 800 shares at $18.08; 200 shares at $18.09; 500 shares at $18.10; 100 shares at $18.11; 1,000 shares at $18.14; 1,000 shares at $18.15; 500 shares at $18.21; 800 shares at $18.22; 2,300 shares at $18.27; 600 shares at $18.28; 200 shares at $18.29; 400 shares at $18.30; 200 shares at $18.31; 2,376 shares at $18.32; 200 shares at $18.33; 2,464 shares at $18.34; 400 shares at $18.35; 300 shares at $18.36; 200 shares at $18.37; 300 shares at $18.38; 400 shares at $18.40; 600 shares at $18.41; 550 shares at $18.42; 1,000 shares at $18.43; 2,210 shares at $18.44; 2,200 shares at $18.45; 600 shares at $18.46; 2,800 shares at $18.47; 1,500 shares at $18.48; 200 shares at $18.49; 3,600 shares at $18.49; 22,020 shares at $18.50; 1,200 shares at $18.51; 2,600 shares at $18.52; 180 shares at $18.53; 2,100 shares at $18.54; 200 shares at $18.55; 100 shares at $18.57; 448 shares at $18.58; Cont. in footnote 4.</footnote>
        <footnote id="F4">300 shares at $18.59; 900 shares at $18.60; 1,200 shares at $18.60; 2,176 shares at $18.61; 100 shares at $18.62; 2,500 shares at $18.62; 200 shares at $18.62; 576 shares at $18.63; 300 shares at $18.64; 1,400 shares at $18.64; 300 shares at $18.65; 300 shares at $18.66; 1,300 shares at $18.67; 400 shares at $18.69; 1,000 shares at $18.69; 1,202 shares at $18.70; 123 shares at $18.71; 600 shares at $18.71; 1,100 shares at $18.72; 100 shares at $18.73; 1,075 shares at $18.75; 2,300 shares at $18.76; 1,060 shares at $18.77; 200 shares at $18.78; 100 shares at $18.81; 740 shares at $18.82; 200 shares at $18.84; 100 shares at $18.89; 200 shares at $18.92; 600  shares at $18.93; 100 shares at $18.93; 188 shares at $18.96; 200 shares at $18.98; 106 shares at $18.99; 400 shares at $19.00; 6 shares at $19.01; 100 shares at $19.03; 300 shares at $19.05; 2,100 shares at $19.06; and 100 shares at $19.06.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>Angelo P. Lopresti, Attorney-in-fact</signatureName>
        <signatureDate>2008-05-08</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SUBMISSION>
