-----BEGIN PRIVACY-ENHANCED MESSAGE-----
Proc-Type: 2001,MIC-CLEAR
Originator-Name: webmaster@www.sec.gov
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MIC-Info: RSA-MD5,RSA,
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 aTrcaMDafE4f6i1bP7y2dg==

<SEC-DOCUMENT>0000775368-04-000009.txt : 20040402
<SEC-HEADER>0000775368-04-000009.hdr.sgml : 20040402
<ACCEPTANCE-DATETIME>20040402154634
ACCESSION NUMBER:		0000775368-04-000009
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20040331
FILED AS OF DATE:		20040402

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			ALLEGHANY CORP /DE
		CENTRAL INDEX KEY:			0000775368
		STANDARD INDUSTRIAL CLASSIFICATION:	TITLE INSURANCE [6361]
		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:			SLATTERY JAMES P
		CENTRAL INDEX KEY:			0000897573

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-09371
		FILM NUMBER:		04713850

	BUSINESS ADDRESS:	
		STREET 1:		375 PARK AVE
		STREET 2:		ALLEGHANY CORP
		CITY:			NEW YORK
		STATE:			NY
		ZIP:			10152
		BUSINESS PHONE:		6129418171

	MAIL ADDRESS:	
		STREET 1:		375 PARK AVE
		STREET 2:		C/O ALLEGHANY CORP
		CITY:			NEW YORK
		STATE:			NY
		ZIP:			10152
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>primary_doc.xml
<DESCRIPTION>PRIMARY DOCUMENT
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0201</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2004-03-31</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

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

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0000897573</rptOwnerCik>
            <rptOwnerName>SLATTERY JAMES P</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>375 PARK AVE</rptOwnerStreet1>
            <rptOwnerStreet2>C/O ALLEGHANY CORP</rptOwnerStreet2>
            <rptOwnerCity>NEW YORK</rptOwnerCity>
            <rptOwnerState>NY</rptOwnerState>
            <rptOwnerZipCode>10152</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>SVP - Insurance</officerTitle>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>625</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
    </nonDerivativeTable>

    <derivativeTable>
        <derivativeTransaction>
            <securityTitle>
                <value>Phantom Stock</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <footnoteId id="F1"/>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2004-03-31</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>15</value>
                </transactionShares>
                <transactionPricePerShare>
                    <footnoteId id="F2"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <footnoteId id="F1"/>
            </exerciseDate>
            <expirationDate>
                <footnoteId id="F1"/>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>15</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>130</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeTransaction>
    </derivativeTable>

    <footnotes>
        <footnote id="F1">The phantom stock units were accrued under the Alleghany Corporation Deferred Compensation Plan and are to be settled in cash upon the earlier of the expiration of the current five year savings benefit deferral period or the termination of the undersigned's employment with Alleghany.</footnote>
        <footnote id="F2">The phantom stock units are convertible into common stock of Alleghany Corporation on a one-for-one basis.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>James P. Slattery</signatureName>
        <signatureDate>2004-04-02</signatureDate>
    </ownerSignature>
</ownershipDocument>

</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
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