##### Table of Contents



UNITED STATES SECURITIES AND EXCHANGE COMMISSION
 Washington, D.C. 20549
 FORM 10-K/A
 Amendment No. 1
 þ
    
    ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES
EXCHANGE ACT OF 1934
 For the fiscal year endedDecember 31, 2007
 OR
 o
    
    TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE
SECURITIES EXCHANGE ACT OF 1934
 For the transition period from  to
 Commission file number: 001-32883
 DARWIN PROFESSIONAL UNDERWRITERS, INC.
 Exact name of registrant as specified in its charter
 Delaware
    
    03-0510450(State or other jurisdiction of
    
    (I.R.S. Employerincorporation or organization)
    
    Identification Number)9 Farm Springs Road, Farmington, CT
    
    06032(Address of principal executive offices)
    
    (Zip Code)
 Registrants telephone number, including area code 860-284-1300
  Title of each class
    
    Name of each exchange on which registeredCommon Stock, $0.01 par value
    
    New York Stock Exchange
 Not applicable
 o þ
 o þ
 þ o
 þ
  Large accelerated filer o
    
    Accelerated filer þ
    
    Non-accelerated filer   o
(Do not check if a smaller reporting company)
    
    Smaller Reporting Company o
 o þ
 17,025,051




---



##### 



Darwin Professional Underwriters, Inc.
 Form 10-K/A
Amendment No. 1
 For Fiscal Year Ended December 31, 2007
 TABLE OF CONTENTS
 Item Description
    
    PagePart II
    
    9A. Controls and Procedures
    
    
    2Part III
    
    10. Directors and Executive Officers and Corporate Governance of the Registrant
    
    
    3Part IV
    
    15. Exhibits and Financial Statement Schedules
    
    
    4Signatures
    
    
    5Exhibits
    
    
    6Ex.31.1:
    
    Certification of Chief Executive OfficerEx. 31.2:
    
    Certification of Chief Financial OfficerEX-31.1: CERTIFICATIONEX-31.2: CERTIFICATION




---



##### Table of Contents



Darwin Professional Underwriters, Inc.
 EXPLANATORY NOTE




---



##### Table of Contents



PART II
 
 Item 9A. Controls and Procedures
 Disclosure Controls and Procedures
  Managements Annual Report on Internal Control over Financial Reporting
   Change in Internal Control over Financial Reporting
  2




---



##### Table of Contents



NYSE CEO Certification
  
 PART III
 
 Item 10. Directors, Executive Officers and Corporate Governance of the Registrant.
 th
 www.darwinpro.com
 Board of Directors.
 Executive Officers.
 Robert J. Asensio.
 Paul C. Martin.
 David J. Newman.
 Paul F. Romano.
 3




---



##### Table of Contents



Mark I. Rosen.
 John L. Sennott, Jr.
 Stephen J. Sills.
 
 PART IV
 
 Item 15. Exhibits and Financial Statement Schedules
  (b) Exhibits.
 31.1
    
    Rule 13a-14(a)/15d-14a Certificate of the Companys Principal Executive
Officer31.2
    
    Rule 13a-14(a)/15d-14a Certificate of the Companys Principal Financial
Officer
 4




---



##### Table of Contents



SIGNATURES
 Pursuant to the requirements of Section 13 or 15(d) of the Securities Exchange Act of 1934, the
registrant has caused this Amendment No. 1 to be signed on its behalf by the undersigned, thereunto
duly authorized.
  
 By:
    
    /s/ Stephen J. Sills
    
    August 28, 2008Stephen J. SillsPresident(Principal Executive Officer)By:
    
    /s/ John L. Sennott, Jr.
    
    August 28, 2008John L. Sennott, Jr.Executive Vice President(Principal Financial Officer)
 5




---



##### Table of Contents



Index to Exhibits
 31.1
    
    Rule 13a-14(a)/15d-14a Certificate of the Companys Principal Executive
Officer31.2
    
    Rule 13a-14(a)/15d-14a Certificate of the Companys Principal Financial
Officer
 
 6