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SECURITIES AND EXCHANGE COMMISSIONWASHINGTON, D.C. 20549

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FORM 10-K/AAMENDMENT NO. 1
TO FORM 10-K

FOR ANNUAL AND TRANSITION REPORTS  PURSUANT TO SECTIONS 13 OR 15(d) OF THE  SECURITIES EXCHANGE ACT OF 1934

(MARK ONE)

|ý | ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE
SECURITIES EXCHANGE ACT OF 1934
|- | ------------------------------------------------------------------------------------

FOR THE FISCAL YEAR ENDED: DECEMBER 31, 2002
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 NO. 000-30981

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GENAISSANCE PHARMACEUTICALS, INC.

(Exact name of registrant as specified in its charter)

Delaware(State or other jurisdiction of
incorporation or organization)

06-1338846(I.R.S. Employer Identification No.)Five Science Park
New Haven, Connecticut(Address of principal executive offices)

06511(Zip Code)


Registrant's
telephone number, including area code:(203) 773-1450

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Securities registered pursuant to Section 12(b) of the Act:    NONE

Securities
registered pursuant to Section 12(g) of the Act:    COMMON STOCK, $.001 PAR VALUE
(Title of each class)

Indicate
by check mark whether the registrant (1) has filed all reports required to be filed by Section 13 or 15(d) of the Securities Exchange Act of 1934 during the
preceding 12 months (or for such shorter period that the registrant was required to file such reports), and (2) has been subject to such filing requirements for the past
90 days. Yes ý    No o

Indicate
by check mark if disclosure of delinquent filers pursuant to Item 405 of Regulation S-K is not contained herein, and will not be contained, to the best of
registrant's knowledge, in definitive proxy or information statements incorporated by reference in Part III of this Form 10-K or any amendment to the
Form 10-K. o

Indicate
by check mark whether the registrant is an accelerated filer (as defined in Exchange Act
Rule 12b-2). Yes o    No ý

The
aggregate market value of voting Common Stock held by non-affiliates of the registrant (without admitting that any person whose shares are not included in such
calculation is an affiliate) on June 30, 2002 was $26,843,669 based on the last reported sale price of the Common Stock on the Nasdaq consolidated transaction reporting system.

Number
of shares of the registrant's class of Common Stock outstanding as of March 28, 2003: 22,846,897.

Documents
Incorporated By Reference:

Items
10, 11, 12, 13 and 15 of Part III (except for information required with respect to our executive officers which is set forth under "Executive Officers" in Item 1A of
Part I of this report) have been omitted from this report, since we expect to file with the Securities and Exchange Commission, not later than 120 days after our fiscal year end, a
definitive proxy statement. The information required by Items 10, 11, 12, 13 and 15 of this report, which will appear in the definitive proxy statement, is incorporated by reference into
Part III of this report.

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EXPLANATORY NOTE

This Amendment No. 1 to Form 10-K is being filed for the sole purpose of including the signature block of Dr. Gualberto Ruano on the
signature page to the Form 10-K as previously filed on March 31, 2003, which was inadvertently omitted. Dr. Ruano is our Vice Chairman, Chief Scientific Officer and a Director.
The signature blocks, as corrected, are submitted in their entirety. This Amendment No. 1 to Form 10-K does not reflect events occurring after the filing of the original Form 10-K
or modify or update those disclosures affected by subsequent events. No other modifications or changes have been made to the Form 10-K as originally filed or the exhibits filed therewith.

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SIGNATURES

Pursuant to the requirements of Section 13 or 15(d) of the Securities Exchange Act of 1934, the Registrant has duly caused this report to be signed on its
behalf by the undersigned, thereunto duly authorized, in the Town of New Haven, Connecticut, on March 31, 2003.

| |  | GENAISSANCE PHARMACEUTICALS, INC.
| |  | ---------------------------------
| |  | By:                              

Pursuant
to the requirements of the Securities Exchange Act of 1934, this report has been signed below by the following persons in the capacities and on the dates indicated.

|Signature                                      |  | Title                                                                                        |  | Date          
|---------------------------------------------- |  | -------------------------------------------------------------------------------------------- |  | --------------
|                                               |  |                                                                                              |  |               
|/s/KEVIN RAKINKevin Rakin                      |  | President, Chief Executive Officer (Principal Executive Officer) and Director                |  | March 31, 2003
|/s/GUALBERTO RUANOGualberto Ruano, M.D., Ph.D. |  | Vice Chairman, Chief Scientific Officer and Director                                         |  | March 31, 2003
|/s/JOSEPH KEYESJoseph Keyes                    |  | Vice President, Chief Financial Officer (Principal Financial Officer and Accounting Officer) |  | March 31, 2003
|/s/JÜRGEN DREWS, M.D.Jürgen Drews, M.D.        |  | Chairman of the Board                                                                        |  | March 31, 2003
|/s/HARRY H. PENNER, JR.Harry H. Penner, Jr.    |  | Director                                                                                     |  | March 31, 2003
|/s/SETH RUDNICK, M.D.Seth Rudnick, M.D.        |  | Director                                                                                     |  | March 31, 2003
|/s/CHRISTOPHER WRIGHTChristopher Wright        |  | Director                                                                                     |  | March 31, 2003

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SIGNATURES

In accordance with Section 13 or 15(d) of the Securities Exchange Act of 1934, the Registrant has duly caused this Amendment to be signed on its behalf by
the undersigned, thereunto duly authorized, in the Town of New Haven, Connecticut, on April 8, 2003.

| |  | GENAISSANCE PHARMACEUTICALS, INC.
| |  | ---------------------------------
| |  | By:                              

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CERTIFICATIONS

I,
Kevin Rakin, certify that:





|Dated: April 8, 2003 |  | /s/KEVIN RAKINKevin Rakin President and Chief Executive
Officer |  | 
|-------------------- |  | --------------------------------------------------------------- |  | 

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CERTIFICATIONS

I,
Joseph Keyes, certify that:





|Dated: April 8, 2003 |  | /s/JOSEPH KEYESJoseph Keyes Vice President and Chief Financial
Officer |  | 
|-------------------- |  | ---------------------------------------------------------------------- |  | 

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