-----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,
 APexgMRkFvSVIqNliZnfhEnVv41OTJ+mtY94p9eNnknlhJyHpDrPfw54k+cLKjOu
 JhKolB2wnJuPgz494/cCSQ==

<SEC-DOCUMENT>0000775368-09-000004.txt : 20090302
<SEC-HEADER>0000775368-09-000004.hdr.sgml : 20090302
<ACCEPTANCE-DATETIME>20090302081614
ACCESSION NUMBER:		0000775368-09-000004
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20090226
FILED AS OF DATE:		20090302
DATE AS OF CHANGE:		20090302

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			ALLEGHANY CORP /DE
		CENTRAL INDEX KEY:			0000775368
		STANDARD INDUSTRIAL CLASSIFICATION:	FIRE, MARINE & CASUALTY INSURANCE [6331]
		IRS NUMBER:				510283071
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		375 PARK AVENUE
		STREET 2:		SUITE 3201
		CITY:			NEW YORK
		STATE:			NY
		ZIP:			10152
		BUSINESS PHONE:		2127521356

	MAIL ADDRESS:	
		STREET 1:		375 PARK AVENUE
		STREET 2:		SUITE 3201
		CITY:			NEW YORK
		STATE:			NY
		ZIP:			10152

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	ALLEGHANY FINANCIAL CORP
		DATE OF NAME CHANGE:	19870115

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			Gorham Roger Bryce
		CENTRAL INDEX KEY:			0001324731

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-09371
		FILM NUMBER:		09645414

	BUSINESS ADDRESS:	
		BUSINESS PHONE:		212.752.1356

	MAIL ADDRESS:	
		STREET 1:		ALLEGHANY CORPORATION
		STREET 2:		375 PARK AVENUE
		CITY:			NEW YORK
		STATE:			NY
		ZIP:			10152
</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>2009-02-26</periodOfReport>

    <issuer>
        <issuerCik>0000775368</issuerCik>
        <issuerName>ALLEGHANY CORP /DE</issuerName>
        <issuerTradingSymbol>Y</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001324731</rptOwnerCik>
            <rptOwnerName>Gorham Roger Bryce</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>ALLEGHANY CORPORATION</rptOwnerStreet1>
            <rptOwnerStreet2>7 TIMES SQUARE TOWER, 17TH FLOOR</rptOwnerStreet2>
            <rptOwnerCity>NEW YORK</rptOwnerCity>
            <rptOwnerState>NY</rptOwnerState>
            <rptOwnerZipCode>10036</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>SVP, Chief Financial Officer</officerTitle>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2009-02-26</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
                <footnoteId id="F1"/>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>1879</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>262.735</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>8033</value>
                    <footnoteId id="F2"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value></value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2009-02-26</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>D</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
                <footnoteId id="F1"/>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>626</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>262.735</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>7407</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value></value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <footnotes>
        <footnote id="F1">Settlement of 1,879 performance shares for Common Stock and $164.395.14 in cash representing the minimum statutory withholding requirements in respect of the award.</footnote>
        <footnote id="F2">Includes shares of Common Stock paid by Alleghany Corporation as a stock dividend on April 25, 2008 to stockholders of record on April 1, 2008.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>Roger B. Gorham</signatureName>
        <signatureDate>2009-02-27</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
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