-----BEGIN PRIVACY-ENHANCED MESSAGE-----
Proc-Type: 2001,MIC-CLEAR
Originator-Name: webmaster@www.sec.gov
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<SEC-DOCUMENT>0001209191-06-031081.txt : 20060518
<SEC-HEADER>0001209191-06-031081.hdr.sgml : 20060518
<ACCEPTANCE-DATETIME>20060518155746
ACCESSION NUMBER:		0001209191-06-031081
CONFORMED SUBMISSION TYPE:	3
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20060517
FILED AS OF DATE:		20060518
DATE AS OF CHANGE:		20060518

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			Darwin Professional Underwriters Inc
		CENTRAL INDEX KEY:			0001355795
		STANDARD INDUSTRIAL CLASSIFICATION:	FIRE, MARINE & CASUALTY INSURANCE [6331]
		IRS NUMBER:				030510450
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		9 FARM SPRINGS ROAD
		CITY:			FARMINGTON
		STATE:			CT
		ZIP:			06032
		BUSINESS PHONE:		860-284-1300

	MAIL ADDRESS:	
		STREET 1:		9 FARM SPRINGS ROAD
		CITY:			FARMINGTON
		STATE:			CT
		ZIP:			06032

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			ALLEGHANY INSURANCE HOLDINGS LLC
		CENTRAL INDEX KEY:			0001140138
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	FILING VALUES:
		FORM TYPE:		3
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-32883
		FILM NUMBER:		06852175

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

	MAIL ADDRESS:	
		STREET 1:		C/O ALLEGHANY CORP
		STREET 2:		375 PARK AVENUE SUITE 3201
		CITY:			NEW YORK
		STATE:			NY
		ZIP:			10152

REPORTING-OWNER:	

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

	FILING VALUES:
		FORM TYPE:		3
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-32883
		FILM NUMBER:		06852176

	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 NAME:	
		FORMER CONFORMED NAME:	ALLEGHANY FINANCIAL CORP
		DATE OF NAME CHANGE:	19870115
</SEC-HEADER>
<DOCUMENT>
<TYPE>3
<SEQUENCE>1
<FILENAME>bny21410_bny1all.xml
<DESCRIPTION>MAIN DOCUMENT DESCRIPTION
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0202</schemaVersion>

    <documentType>3</documentType>

    <periodOfReport>2006-05-17</periodOfReport>

    <noSecuritiesOwned>0</noSecuritiesOwned>

    <issuer>
        <issuerCik>0001355795</issuerCik>
        <issuerName>Darwin Professional Underwriters Inc</issuerName>
        <issuerTradingSymbol>DR</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0000775368</rptOwnerCik>
            <rptOwnerName>ALLEGHANY CORP /DE</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>7 TIMES SQUARE TOWER</rptOwnerStreet1>
            <rptOwnerStreet2>17TH FLOOR</rptOwnerStreet2>
            <rptOwnerCity>NEW YORK</rptOwnerCity>
            <rptOwnerState>NY</rptOwnerState>
            <rptOwnerZipCode>10036</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001140138</rptOwnerCik>
            <rptOwnerName>ALLEGHANY INSURANCE HOLDINGS LLC</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>7 TIMES SQUARE TOWER</rptOwnerStreet1>
            <rptOwnerStreet2>17TH FLOOR</rptOwnerStreet2>
            <rptOwnerCity>NEW YORK</rptOwnerCity>
            <rptOwnerState>NY</rptOwnerState>
            <rptOwnerZipCode>10036</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Series A Preferred Stock</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>114860</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>See Footnote</value>
                    <footnoteId id="F1"/>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Series C Preferred Stock</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>2465</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>See Footnote</value>
                    <footnoteId id="F1"/>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
    </nonDerivativeTable>

    <derivativeTable>
        <derivativeHolding>
            <securityTitle>
                <value>Series B Convertible Preferred Stock</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>219.0867</value>
            </conversionOrExercisePrice>
            <exerciseDate>
                <footnoteId id="F2"/>
            </exerciseDate>
            <expirationDate>
                <footnoteId id="F2"/>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>900000</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>See Footnote</value>
                    <footnoteId id="F1"/>
                </natureOfOwnership>
            </ownershipNature>
        </derivativeHolding>
    </derivativeTable>

    <footnotes>
        <footnote id="F1">The reported securities are owned directly by Alleghany Insurance Holdings LLC (&quot;AIHL&quot;) and are beneficially owned indirectly by Alleghany Corporation (&quot;Alleghany&quot;), which is the sole stockholder of AIHL. This report if filed jointly by Alleghany and by AIHL, 7 Times Square Tower, New York, New York 10036. Because AIHL owns, and Alleghany beneficially owns, more than 90% of the issued and outstanding voting securities of Darwin Professional Underwriters, Inc. (&quot;DR&quot;) and AIHL has elected three Alleghany officers to serve as its representatives on the Board of Directors of DR, each of AIHL and Alleghany may be deemed to be a director by deputization of DR.</footnote>
        <footnote id="F2">The shares of Series B Convertible Preferred Stock are convertible at any time, at the option of the holder, into shares of Common Stock. The shares of Series B Convertible Preferred Stock do not have an expiration date.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>/s/ Weston M. Hicks</signatureName>
        <signatureDate>2006-05-17</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>/s/ Weston M. Hicks</signatureName>
        <signatureDate>2006-05-17</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
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