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Proc-Type: 2001,MIC-CLEAR
Originator-Name: webmaster@www.sec.gov
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 TWSM7vrzLADbmYQaionwg5sDW3P6oaM5D3tdezXMm7z1T+B+twIDAQAB
MIC-Info: RSA-MD5,RSA,
 FOxmqc5NK5IlDs3UXIZlvaflLECu8KcsSOREQaSGPMLOdnWO1m8zspPYrZbiDN7t
 lqIghF3+F2pIW4uM4Mf2Pg==

<SEC-DOCUMENT>0001179110-08-015265.txt : 20080814
<SEC-HEADER>0001179110-08-015265.hdr.sgml : 20080814
<ACCEPTANCE-DATETIME>20080814172238
ACCESSION NUMBER:		0001179110-08-015265
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20080812
FILED AS OF DATE:		20080814
DATE AS OF CHANGE:		20080814

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			INVESTMENT TECHNOLOGY GROUP INC
		CENTRAL INDEX KEY:			0000920424
		STANDARD INDUSTRIAL CLASSIFICATION:	SECURITY BROKERS, DEALERS & FLOTATION COMPANIES [6211]
		IRS NUMBER:				133757717
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		380 MADISON AVE
		STREET 2:		4TH FLOOR
		CITY:			NEW YORK
		STATE:			NY
		ZIP:			10017
		BUSINESS PHONE:		2125884000

	MAIL ADDRESS:	
		STREET 1:		380 MADISON AVE
		STREET 2:		4TH FLOOR
		CITY:			NEW YORK
		STATE:			NY
		ZIP:			10017

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			HUCK ANTHONY J
		CENTRAL INDEX KEY:			0001225745

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-32722
		FILM NUMBER:		081020531

	BUSINESS ADDRESS:	
		BUSINESS PHONE:		6072553645

	MAIL ADDRESS:	
		STREET 1:		C/O ITG INC
		STREET 2:		380 MADISON AVENUE
		CITY:			NEW YORK
		STATE:			NY
		ZIP:			10017
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>edgar.xml
<DESCRIPTION>FORM 4 -
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0303</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2008-08-12</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0000920424</issuerCik>
        <issuerName>INVESTMENT TECHNOLOGY GROUP INC</issuerName>
        <issuerTradingSymbol>ITG</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001225745</rptOwnerCik>
            <rptOwnerName>HUCK ANTHONY J</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O ITG INC.</rptOwnerStreet1>
            <rptOwnerStreet2>380 MADISON AVENUE</rptOwnerStreet2>
            <rptOwnerCity>NEW YORK</rptOwnerCity>
            <rptOwnerState>NY</rptOwnerState>
            <rptOwnerZipCode>10017</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>Managing Director</officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2008-08-12</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>S</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>773</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>32.63</value>
                    <footnoteId id="F1"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>57325</value>
                    <footnoteId id="F2"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <derivativeTable></derivativeTable>

    <footnotes>
        <footnote id="F1">Sales made by the Reporting Person in connection with this Form 4 were made at $32.63 and $32.64, and the Reporting Person hereby undertakes to provide upon request by the Securities and Exchange Commission staff, the company, or any security holder of the company, full information regarding the number of shares sold at each separate price.</footnote>
        <footnote id="F2">The Amount of Securities Beneficially Owned does not include 258 shares of Common Stock allocated to the Reporting Person under the ESOP Trust, and the Reporting Person shares investment power with respect to the 8,341 shares of Common Stock</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>P. Mats Goebels, by Power of Attorney filed with Form 4 dated October 16, 2002</signatureName>
        <signatureDate>2008-08-14</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
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