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Proc-Type: 2001,MIC-CLEAR
Originator-Name: webmaster@www.sec.gov
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MIC-Info: RSA-MD5,RSA,
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<SEC-DOCUMENT>0000874501-10-000001.txt : 20100106
<SEC-HEADER>0000874501-10-000001.hdr.sgml : 20100106
<ACCEPTANCE-DATETIME>20100106114918
ACCESSION NUMBER:		0000874501-10-000001
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		2
CONFORMED PERIOD OF REPORT:	20100104
FILED AS OF DATE:		20100106
DATE AS OF CHANGE:		20100106

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			DEROSA PAUL R
		CENTRAL INDEX KEY:			0001221300

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-10777
		FILM NUMBER:		10510370

	MAIL ADDRESS:	
		STREET 1:		645 MADISON AVENUE 13TH FL
		CITY:			NEW YORK
		STATE:			NY
		ZIP:			10020

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			AMBAC FINANCIAL GROUP INC
		CENTRAL INDEX KEY:			0000874501
		STANDARD INDUSTRIAL CLASSIFICATION:	SURETY INSURANCE [6351]
		IRS NUMBER:				133621676
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		ONE STATE ST PLZ
		CITY:			NEW YORK
		STATE:			NY
		ZIP:			10004
		BUSINESS PHONE:		2126680340

	MAIL ADDRESS:	
		STREET 1:		ONE STATE ST PLZ
		CITY:			NEW YORK
		STATE:			NY
		ZIP:			10004

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	AMBAC INC /DE/
		DATE OF NAME CHANGE:	19930328
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>edgar.xml
<DESCRIPTION>PRIMARY DOCUMENT
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0303</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2010-01-04</periodOfReport>

    <issuer>
        <issuerCik>0000874501</issuerCik>
        <issuerName>AMBAC FINANCIAL GROUP INC</issuerName>
        <issuerTradingSymbol>ABK</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001221300</rptOwnerCik>
            <rptOwnerName>DEROSA PAUL R</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>AMBAC FINANCIAL GROUP, INC.</rptOwnerStreet1>
            <rptOwnerStreet2>ONE STATE STREET PLAZA</rptOwnerStreet2>
            <rptOwnerCity>NEW YORK</rptOwnerCity>
            <rptOwnerState>NY</rptOwnerState>
            <rptOwnerZipCode>10004</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>78488</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value></value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
    </nonDerivativeTable>

    <derivativeTable>
        <derivativeTransaction>
            <securityTitle>
                <value>Phantom Stock Units</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <footnoteId id="F1"/>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2010-01-04</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>48765</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>.81</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <footnoteId id="F2"/>
            </exerciseDate>
            <expirationDate>
                <footnoteId id="F2"/>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>48765</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>127652</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value></value>
                </natureOfOwnership>
            </ownershipNature>
        </derivativeTransaction>
    </derivativeTable>

    <footnotes>
        <footnote id="F1">Each Phantom Stock Unit converts to common stock on a one to one basis.</footnote>
        <footnote id="F2">These Phantom Stock Units (&quot;PSUs&quot;) were acquired under the Issuer's Deferred Compensation Plan and represent 25% of the Reporting Person's Annual Retainer Fees for serving as a director and 100% of his Meeting Fees earned during the fourth quarter of 2009.  These PSUs are to be settled 100% in cash upon the Reporting Person's retirement or resignation from the Issuer's Board of Directors or on an earlier date previously selected by the Reporting Person.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>Patricia LoCascio, Attorney in Fact for Paul DeRosa</signatureName>
        <signatureDate>2010-01-06</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
<DOCUMENT>
<TYPE>EX-24
<SEQUENCE>2
<FILENAME>derosa.txt
<DESCRIPTION>POWER OF ATTORNEY
<TEXT>
POWER OF ATTORNEY

I, Paul DeRosa, do hereby nominate, constitute and appoint each
of Anne Gill Kelly, Kevin J. Doyle, Marianna Blanch,
Stacey B. Spain and Patricia Lo Cascio, as my true and lawful
agent and attorney-in-fact, with full power and authority to act
hereunder, in his or her discretion, in my
name and on my behalf as fully as I could if I were present and acting
in person, to make any and all required or voluntary filings under
Section 16(a) of the Securities Exchange Act of 1934,as amended (the
"Exchange Act"), and the applicable rules and regulations
thereunder, with the Securities and Exchange Commission, the New York
Stock Exchange, Ambac Financial Group, Inc., a Delaware corporation
(the "Company"), and any other person or entity to which such filings
may be required under Section 16(a) of the Exchange Act as a result of
my service as an officer of the Company or beneficial ownership
(within the meaning of Section 16(a) of the Exchange Act) of more than
ten percent of any class of equity securities
of the Company.

I hereby consent to, ratify and confirm all that each said attorney-in-fact
shall do or cause to be done by virtue of this Power of Attorney.  I hereby
acknowledge that each attorney-in-fact, in serving in such capacity at my
request, is not assuming, nor is the Company assuming, any of my
responsibilities to comply with Section 16 of the Exchange Act.

This Power of Attorney shall remain in full force and effect from this
date forward for so long as I am an officer or director of the Company
and for such time thereafter as may be necessary to make any such filings
or until revoked or modified by me.  I hereby revoke all prior powers of
attorney relating to the foregoing acts.

IN WITNESS WHEREOF, I have hereunto signed my name this 30th day of
June 2008.

/s/ Paul DeRosa
PAUL DEROSA
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
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