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Proc-Type: 2001,MIC-CLEAR
Originator-Name: webmaster@www.sec.gov
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<SEC-DOCUMENT>0001197817-10-000008.txt : 20100727
<SEC-HEADER>0001197817-10-000008.hdr.sgml : 20100727
<ACCEPTANCE-DATETIME>20100727174355
ACCESSION NUMBER:		0001197817-10-000008
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20100723
FILED AS OF DATE:		20100727
DATE AS OF CHANGE:		20100727

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			BLACK RICHARD B
		CENTRAL INDEX KEY:			0001199697

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	000-25705
		FILM NUMBER:		10972494

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			GSI GROUP INC
		CENTRAL INDEX KEY:			0001076930
		STANDARD INDUSTRIAL CLASSIFICATION:	MISCELLANEOUS ELECTRICAL MACHINERY, EQUIPMENT & SUPPLIES [3690]
		IRS NUMBER:				980110412
		STATE OF INCORPORATION:			A3
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		125 MIDDLESEX TURNPIKE
		STREET 2:		.
		CITY:			BEDFORD
		STATE:			MA
		ZIP:			01730
		BUSINESS PHONE:		781-266-5700

	MAIL ADDRESS:	
		STREET 1:		125 MIDDLESEX TURNPIKE
		STREET 2:		.
		CITY:			BEDFORD
		STATE:			MA
		ZIP:			01730

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	GSI LUMONICS INC
		DATE OF NAME CHANGE:	19990401

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	GSI LUMONICS
		DATE OF NAME CHANGE:	19990331

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	LUMONICS INC
		DATE OF NAME CHANGE:	19990115
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>primary_doc.xml
<DESCRIPTION>PRIMARY DOCUMENT
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0303</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2010-07-23</periodOfReport>

    <notSubjectToSection16>1</notSubjectToSection16>

    <issuer>
        <issuerCik>0001076930</issuerCik>
        <issuerName>GSI GROUP INC</issuerName>
        <issuerTradingSymbol>LASR.PK</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001199697</rptOwnerCik>
            <rptOwnerName>BLACK RICHARD B</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O GSI GROUP INC.</rptOwnerStreet1>
            <rptOwnerStreet2>125 MIDDLESEX TURNPIKE</rptOwnerStreet2>
            <rptOwnerCity>BEDFORD</rptOwnerCity>
            <rptOwnerState>MA</rptOwnerState>
            <rptOwnerZipCode>01730-1409</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>2010-07-23</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>J</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
                <footnoteId id="F1"/>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>25007</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>0</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2010-07-23</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
                <footnoteId id="F1"/>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>127279</value>
                    <footnoteId id="F2"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>127279</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2010-07-23</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>M</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
                <footnoteId id="F3"/>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>39083</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>1.8</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>166362</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <derivativeTable>
        <derivativeTransaction>
            <securityTitle>
                <value>Subscription Rights (right to buy)</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>1.8</value>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2010-07-23</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>M</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
                <footnoteId id="F3"/>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>39083</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>1.8</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <value>2010-07-07</value>
            </exerciseDate>
            <expirationDate>
                <value>2010-07-23</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>39083</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>39083</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeTransaction>
    </derivativeTable>

    <footnotes>
        <footnote id="F1">On July 23, 2010 (the &quot;Effective Date&quot;), the Final Fourth Modified Joint Chapter 11 Plan of Reorganization for MES International Inc. (&quot;MES&quot;), GSI Group Inc. (the &quot;Company&quot;) and GSI Group Corporation (&quot;GSI&quot; and, collectively with MES and the Company, the &quot;Debtors&quot;), as confirmed by the United States Bankruptcy Court for the District of Delaware on May 27, 2010 (the &quot;Plan&quot;), became effective and the Debtors emerged from Chapter 11 protection.  In connection with the Plan, (i) all common shares and vested share rights of the Company that were outstanding prior to the Effective Date (collectively, the &quot;Old Common Shares&quot;) were cancelled and (ii) new common shares of the Company, as reorganized (&quot;New Common Shares&quot;), were issued to holders of such Old Common Shares under the Final Plan on a one-for-one basis, subject to a 6.165% escrow as contemplated in the Plan.</footnote>
        <footnote id="F2">Includes 79,033 New Common Shares issued in exchange for certain vested share rights of the Company and 23,465 New Common Shares issued in exchange for Old Common Shares held by the Reporting Person.</footnote>
        <footnote id="F3">Pursuant to the rights offering contemplated under the Plan, the Reporting Person elected to subscribe for New Common Shares of the Company at a pruchase price of $1.80 per New Common Shares.  In connection with such election, the Company issued 39,083 New Common Shares to the Reporting Company on the Effective Date of the Plan.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>Anthony J. Bellantuoni, Attorney-in-Fact</signatureName>
        <signatureDate>2010-07-27</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
-----END PRIVACY-ENHANCED MESSAGE-----