-----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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 HzdUQGpKjXax28aSaFmO2Q==

<SEC-DOCUMENT>0000775368-04-000002.txt : 20040121
<SEC-HEADER>0000775368-04-000002.hdr.sgml : 20040121
<ACCEPTANCE-DATETIME>20040121171044
ACCESSION NUMBER:		0000775368-04-000002
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20040120
FILED AS OF DATE:		20040121

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:			CARMICHAEL DAN R
		CENTRAL INDEX KEY:			0001014160

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-09371
		FILM NUMBER:		04535728

	BUSINESS ADDRESS:	
		STREET 1:		C/O OHIO CASUALTY CORP
		STREET 2:		9540 SEWARD RD
		CITY:			FAIRFIELD
		STATE:			OH
		ZIP:			45014
		BUSINESS PHONE:		5136032600

	MAIL ADDRESS:	
		STREET 1:		9450 SEWARD RD
		CITY:			FAIRFIELD
		STATE:			OH
		ZIP:			45014
</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>2004-01-20</periodOfReport>


    <notSubjectToSection16>0</notSubjectToSection16>

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

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001014160</rptOwnerCik>
            <rptOwnerName>CARMICHAEL DAN R</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>9450 SEWARD RD</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>FAIRFIELD</rptOwnerCity>
            <rptOwnerState>OH</rptOwnerState>
            <rptOwnerZipCode>45014</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>

        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2004-01-20</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>M</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>1922</value>
                    <footnoteId id="F1"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>73.7427</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>3636</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>

    </nonDerivativeTable>

    <derivativeTable>

        <derivativeTransaction>
            <securityTitle>
                <value>Option (right to buy)</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>73.7427</value>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2004-01-20</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>M</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>1</value>
                </transactionShares>
                <transactionPricePerShare>
                    <footnoteId id="F2"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <footnoteId id="F2"/>
            </exerciseDate>
            <expirationDate>
                <value>2004-04-25</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>1922</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>9</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeTransaction>

    </derivativeTable>

    <footnotes>
        <footnote id="F1">The option, originally granted for 1,000 shares of common stock at an exercise price of $141.75, was adjusted for 2% stock dividends paid in April 1996, 1997, 1999, 2000, 2001, 2002 and 2003 and for the spin off of Chicago Title Corporation in June 1998.</footnote>
        <footnote id="F2">One third of such option became exercisable on each of the first, second and third anniversaries of the date of grant.</footnote>
    </footnotes>


    <ownerSignature>
        <signatureName>Christopher K. Dalrymple, Attorney-in-Fact</signatureName>
        <signatureDate>2004-01-21</signatureDate>
    </ownerSignature>

</ownershipDocument>

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