-----BEGIN PRIVACY-ENHANCED MESSAGE-----
Proc-Type: 2001,MIC-CLEAR
Originator-Name: webmaster@www.sec.gov
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 TWSM7vrzLADbmYQaionwg5sDW3P6oaM5D3tdezXMm7z1T+B+twIDAQAB
MIC-Info: RSA-MD5,RSA,
 ORpOopzuP51tKoF9RnRgaz0b9E1ca6qEvhXgp0zazk/z6V6KWSsUtspBHETJVDXr
 xIUJxChJEf8M2gAm+I1yMg==

<SEC-DOCUMENT>0001140361-10-041798.txt : 20101020
<SEC-HEADER>0001140361-10-041798.hdr.sgml : 20101020
<ACCEPTANCE-DATETIME>20101020200501
ACCESSION NUMBER:		0001140361-10-041798
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20101018
FILED AS OF DATE:		20101020
DATE AS OF CHANGE:		20101020

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			STEINBERG JOSEPH S
		CENTRAL INDEX KEY:			0000924255
		STATE OF INCORPORATION:			NY
		FISCAL YEAR END:			1231

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-14947
		FILM NUMBER:		101133735

	MAIL ADDRESS:	
		STREET 1:		C/O LEUCADIA NATIONAL CORP
		STREET 2:		315 PARK AVENUE SOUTH
		CITY:			NEW YORK
		STATE:			NY
		ZIP:			10010

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			JEFFERIES GROUP INC /DE/
		CENTRAL INDEX KEY:			0001084580
		STANDARD INDUSTRIAL CLASSIFICATION:	SECURITY BROKERS, DEALERS & FLOTATION COMPANIES [6211]
		IRS NUMBER:				954719745
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1130

	BUSINESS ADDRESS:	
		STREET 1:		520 MADISON AVENUE
		STREET 2:		12TH FLOOR
		CITY:			NEW  YORK
		STATE:			NY
		ZIP:			10022
		BUSINESS PHONE:		212-284-2550

	MAIL ADDRESS:	
		STREET 1:		520 MADISON AVENUE
		STREET 2:		12TH FLOOR
		CITY:			NEW YORK
		STATE:			NY
		ZIP:			10022

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	JEF HOLDING CO INC
		DATE OF NAME CHANGE:	19990419
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>doc1.xml
<DESCRIPTION>FORM 4
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0303</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2010-10-18</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0001084580</issuerCik>
        <issuerName>JEFFERIES GROUP INC /DE/</issuerName>
        <issuerTradingSymbol>JEF</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0000924255</rptOwnerCik>
            <rptOwnerName>STEINBERG JOSEPH S</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O LEUCADIA NATIONAL CORPORATION</rptOwnerStreet1>
            <rptOwnerStreet2>315 PARK AVENUE SOUTH</rptOwnerStreet2>
            <rptOwnerCity>NEW YORK</rptOwnerCity>
            <rptOwnerState>NY</rptOwnerState>
            <rptOwnerZipCode>10010</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle></officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>14485</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2010-10-18</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>P</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>146000</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>23.449</value>
                    <footnoteId id="F1"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>48731385</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>See Explanation</value>
                    <footnoteId id="F2"/>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2010-10-19</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>P</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>500000</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>23.4472</value>
                    <footnoteId id="F3"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>49231385</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>See Explanation</value>
                    <footnoteId id="F2"/>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2010-10-20</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>P</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>45000</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>23.4313</value>
                    <footnoteId id="F4"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>49276385</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>See Explanation</value>
                    <footnoteId id="F2"/>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <derivativeTable></derivativeTable>

    <footnotes>
        <footnote id="F1">Reflects weighted average per share purchase price of separately priced transactions at a range of $23.09-$23.55. Upon the request of the Commission or a security holder of the issuer, full information regarding the number of shares purchased at each separate price will be provided to the requesting party.</footnote>
        <footnote id="F2">Reflects shares of Issuer's common stock beneficially owned by Leucadia National Corporation (&quot;Leucadia&quot;). The Reporting Person is a significant shareholder, director and President of Leucadia.  The Reporting Person disclaims beneficial ownership of the Issuer's common stock beneficially owned by Leucadia, except to the extent of his pecuniary interest, if any.</footnote>
        <footnote id="F3">Reflects weighted average per share purchase price of separately priced transactions at a range of $23.28-$23.60. Upon the request of the Commission or a security holder of the issuer, full information regarding the number of shares purchased at each separate price will be provided to the requesting party.</footnote>
        <footnote id="F4">Reflects weighted average per share purchase price of separately priced transactions at a range of $23.37-$23.60. Upon the request of the Commission or a security holder of the issuer, full information regarding the number of shares purchased at each separate price will be provided to the requesting party.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>/s/ Joseph S. Steinberg</signatureName>
        <signatureDate>2010-10-20</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
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