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Proc-Type: 2001,MIC-CLEAR
Originator-Name: webmaster@www.sec.gov
Originator-Key-Asymmetric:
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 TWSM7vrzLADbmYQaionwg5sDW3P6oaM5D3tdezXMm7z1T+B+twIDAQAB
MIC-Info: RSA-MD5,RSA,
 NPpf+YNsoWiopySPrJJXJDgdT/CZKZYalHVuB4gIzlFa4om4zK8m2vRPblAC6Dc0
 anaEKmjsSuzKURVyYe6o9g==

<SEC-DOCUMENT>0001179110-05-016160.txt : 20050811
<SEC-HEADER>0001179110-05-016160.hdr.sgml : 20050811
<ACCEPTANCE-DATETIME>20050811155441
ACCESSION NUMBER:		0001179110-05-016160
CONFORMED SUBMISSION TYPE:	3
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20050811
FILED AS OF DATE:		20050811
DATE AS OF CHANGE:		20050811

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			Refco Inc.
		CENTRAL INDEX KEY:			0001321746
		STANDARD INDUSTRIAL CLASSIFICATION:	SECURITY & COMMODITY BROKERS, DEALERS, EXCHANGES & SERVICES [6200]
		IRS NUMBER:				202537426

	BUSINESS ADDRESS:	
		STREET 1:		ONE WORLD FINANCIAL CENTER
		STREET 2:		200 LIBERTY STREET, TOWER A
		CITY:			NEW YORK
		STATE:			NY
		ZIP:			10281
		BUSINESS PHONE:		212-693-7000

	MAIL ADDRESS:	
		STREET 1:		ONE WORLD FINANCIAL CENTER
		STREET 2:		200 LIBERTY STREET, TOWER A
		CITY:			NEW YORK
		STATE:			NY
		ZIP:			10281

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			LEE THOMAS H ADVISORS LLC
		CENTRAL INDEX KEY:			0001260943
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	FILING VALUES:
		FORM TYPE:		3
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-32604
		FILM NUMBER:		051017102

	BUSINESS ADDRESS:	
		STREET 1:		C/O THOMAS H. LEE PARTNERS, L.P.
		STREET 2:		100 FEDERAL STREET, 35TH FLOOR
		CITY:			BOSTON
		STATE:			MA
		ZIP:			02110
		BUSINESS PHONE:		6172271050

	MAIL ADDRESS:	
		STREET 1:		C/O THOMAS H. LEE PARTNERS, L.P.
		STREET 2:		100 FEDERAL STREET, 35TH FLOOR
		CITY:			BOSTON
		STATE:			MA
		ZIP:			02110
</SEC-HEADER>
<DOCUMENT>
<TYPE>3
<SEQUENCE>1
<FILENAME>edgar.xml
<DESCRIPTION>FORM 3 -
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0202</schemaVersion>

    <documentType>3</documentType>

    <periodOfReport>2005-08-11</periodOfReport>

    <noSecuritiesOwned>0</noSecuritiesOwned>

    <issuer>
        <issuerCik>0001321746</issuerCik>
        <issuerName>Refco Inc.</issuerName>
        <issuerTradingSymbol>RFX</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001260943</rptOwnerCik>
            <rptOwnerName>LEE THOMAS H ADVISORS LLC</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O THOMAS H. LEE PARTNERS, LP</rptOwnerStreet1>
            <rptOwnerStreet2>100 FEDERAL STREET, 35TH FLOOR</rptOwnerStreet2>
            <rptOwnerCity>BOSTON</rptOwnerCity>
            <rptOwnerState>MA</rptOwnerState>
            <rptOwnerZipCode>02110</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle></officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>48721076</value>
                    <footnoteId id="F1"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>See Note (2)</value>
                    <footnoteId id="F2"/>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
    </nonDerivativeTable>

    <derivativeTable></derivativeTable>

    <footnotes>
        <footnote id="F1">Represents shares of the Issuer held directly by Thomas H. Lee Equity Fund V, L.P. (&quot;Equity&quot;), Thomas H. Lee Parallel Fund V, L.P. (&quot;Parallel&quot;), and Thomas H. Lee Equity (Cayman) Fund V, L.P. (&quot;Cayman&quot;, and together with Equity and Parallel, the &quot;Funds&quot;).</footnote>
        <footnote id="F2">The reporting person is the general partner of Thomas H. Lee Partners, L.P., which is the manager of THL Equity Advisors V, LLC , which, in turn, is the general partner of each of the Funds. As such, the reporting person may be deemed to beneficially own the shares of the Issuer owned directly by each of the Funds.  The reporting person disclaims beneficial ownership of such shares, and this report shall not be deemed an admission that the reporting person is the beneficial owner of the securities for the purpose of Section 16 or for any other purpose, except to the extent of his pecuniary interest therein.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>/s/Scott M. Sperling</signatureName>
        <signatureDate>2005-08-11</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
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