Ownership Submission
FORM 3
 UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

INITIAL STATEMENT OF BENEFICIAL OWNERSHIP OF SECURITIES

Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934, Section 17(a) of the Public Utility Holding Company Act of 1935 or Section 30(h) of the Investment Company Act of 1940
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(Print or Type Responses)
1. Name and Address of Reporting Person *
  ALLEGHANY CORP /DE
 2. Date of Event Requiring Statement (Month/Day/Year)
05/17/2006		 3. Issuer Name and Ticker or Trading Symbol
Darwin Professional Underwriters Inc [DR]
(Last)
(First)
(Middle)
7 TIMES SQUARE TOWER, 17TH FLOOR		 4. Relationship of Reporting Person(s) to Issuer
(Check all applicable)
__X__ Director __X__ 10% Owner
_____ Officer (give title below) _____ Other (specify below)
5. If Amendment, Date Original Filed(Month/Day/Year)
(Street)

NEW YORK, NY 10036		 6. Individual or Joint/Group Filing(Check Applicable Line)
___ Form filed by One Reporting Person
_X_ Form filed by More than One Reporting Person
(City)
(State)
(Zip)
Table I - Non-Derivative Securities Beneficially Owned
1.Title of Security
(Instr. 4)		 2. Amount of Securities Beneficially Owned
(Instr. 4)		 3. Ownership Form: Direct (D) or Indirect (I)
(Instr. 5)		 4. Nature of Indirect Beneficial Ownership
(Instr. 5)
Series A Preferred Stock 114,860
I
See Footnote (1)
Series C Preferred Stock 2,465
I
See Footnote (1)

Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly. SEC 1473 (7-02)
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Table II - Derivative Securities Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security
(Instr. 4)		 2. Date Exercisable and Expiration Date
(Month/Day/Year)		 3. Title and Amount of Securities Underlying Derivative Security
(Instr. 4)		 4. Conversion or Exercise Price of Derivative Security 5. Ownership Form of Derivative Security: Direct (D) or Indirect (I)
(Instr. 5)		 6. Nature of Indirect Beneficial Ownership
(Instr. 5)
Date Exercisable Expiration Date Title Amount or Number of Shares
Series B Convertible Preferred Stock   (2)   (2) Common Stock 900,000 $ 219.0867 I See Footnote (1)

Reporting Owners

Reporting Owner Name / Address Relationships
Director 10% Owner Officer Other
ALLEGHANY CORP /DE
7 TIMES SQUARE TOWER
17TH FLOOR
NEW YORK, NY 10036		   X   X    
ALLEGHANY INSURANCE HOLDINGS LLC
7 TIMES SQUARE TOWER
17TH FLOOR
NEW YORK, NY 10036		   X   X    

Signatures

/s/ Weston M. Hicks 05/17/2006
**Signature of Reporting Person Date
/s/ Weston M. Hicks 05/17/2006
**Signature of Reporting Person Date

Explanation of Responses:

* If the form is filed by more than one reporting person, see Instruction 5(b)(v).
** Intentional misstatements or omissions of facts constitute Federal Criminal Violations. See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).
(1) The reported securities are owned directly by Alleghany Insurance Holdings LLC ("AIHL") and are beneficially owned indirectly by Alleghany Corporation ("Alleghany"), 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. ("DR") 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.
(2) 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.

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