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                                                                   Exhibit 10.21


                   CONFIDENTIALITY & NONCOMPETITION AGREEMENT

         CONFIDENTIALITY & NONCOMPETITION AGREEMENT (this "Agreement"), made and
entered into as of November 16, 1999 (the "Effective Date"), by and between
GENAISSANCE PHARMACEUTICALS, INC. (the "Corporation"), a Delaware corporation
with its principal office at 5 Science Park, New Haven, Connecticut, 06511, and
RICHARD JUDSON ("Executive"), an individual who resides at 42 Barker Hill Drive,
Guilford, CT 06437.

         WHEREAS, the Corporation and Executive desire to continue their
employment relationship on the terms and conditions set forth herein;

         NOW, THEREFORE, in consideration of the mutual covenants and agreements
contained herein, and other good and valuable consideration, the receipt and
sufficiency of which is hereby acknowledged, the parties agree as follows:

         1.   EMPLOYMENT. The Corporation hereby promotes Executive to Vice
President, Informatics of the Corporation, and Executive hereby accepts such
position. Executive acknowledges that this Agreement is not a contract of
employment between Executive and the Corporation and that Executive is an
employee at will of the Corporation.

         2.   COMPENSATION. As compensation for the services to be rendered by
Executive to the Corporation as Vice President, Informatics, the Corporation
shall pay Executive and provide Executive with the following compensation and
enhanced benefits which Executive agrees to accept in full satisfaction for his
services:

              a.   BASE SALARY. The Corporation shall pay Executive a Base
         Salary, payable in equal installments at such payment intervals as are
         the usual custom of the Corporation, but not less often than monthly,
         at an annual rate of $125,000, less such deductions or amounts to be
         withheld as shall be required by applicable law (the "Base Salary").

              b.   BONUSES. Hereafter, during the Executive's employment with
         the Corporation, the Corporation may pay Executive bonuses according to
         the Corporation's existing policies and at the discretion of the
         Corporation's President who shall review Executive's achievements in
         meeting the financial and performance goals of the Corporation for its
         most recent fiscal year. Each bonus, if any, shall be paid in addition
         to the Base Salary.

              c.   ENHANCED BENEFITS. Executive shall be entitled to participate
         in the Corporation's Stock Option Plan (the "Plan") and the Corporation
         shall grant Executive an option to purchase a total of 50,000 shares of
         the Corporation's common stock at an exercise price per share equal to
         $3.00 (the "Option"). The Option shall vest ratably over a 4 year
         period beginning on the date of grant of the Option. The Option shall
         be set forth


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         in a separate agreement embodying the grant of the Option which shall
         be otherwise in the form stipulated in the Plan.

         3.   INVENTIONS AND IMPROVEMENTS. Executive acknowledges, covenants and
agrees that the Corporation shall be the sole owner of all the fruits and
proceeds of Executive's services to the Corporation, including but not limited
to all writings, inventions, discoveries, designs, systems, processes, software
or other improvements relating to the business or products of the Corporation,
whether or not patentable, registerable, or copyrightable, which Executive may,
alone or with others, conceive, create, develop, produce or make during or as a
result of his employment with the Corporation (collectively, the "Invention"),
free and clear of any claims by Executive of any kind or character whatsoever
other than Executive's rights to compensation hereunder. Executive agrees that
he shall disclose each of the Inventions promptly and completely to the
Corporation, and shall, at the request of the President of the Corporation,
execute such assignments, certificates or other instruments as the President of
the Corporation, from time to time deems necessary or desirable to evidence,
establish, maintain, perfect, protect, enforce or defend the Corporation's
right, title and interest in or to any or all of the Inventions.

         4.   NON-DISCLOSURE OF CONFIDENTIAL INFORMATION.

              a.   Executive acknowledges that, in and as a result of his
         employment by the Corporation, he will be making use of, acquiring
         and/or adding to the Corporation's Confidential Information (as
         hereinafter defined). As a material inducement to the Corporation to
         promote Executive to Vice President, Informatics and to pay Executive
         the compensation and benefits set forth in this Agreement, Executive
         covenants and agrees that he shall not, at any time during or following
         the term of his employment with the Corporation, directly or indirectly
         divulge or disclose for any purposes whatsoever, any Confidential
         Information that has been obtained by, or disclosed to, him as a result
         of his employment with the Corporation. For purposes of this Agreement,
         "Confidential Information" means, collectively, all confidential
         matters and materials of the Corporation, including without limitation,
         the Corporation's proprietary information, inventions, trade secrets,
         knowledge, data, know-how, intellectual property, systems, procedures,
         manuals, pricing policies, operational methods and information relating
         to the Corporation's products, processes, formulae, business plans,
         marketing plans and strategies, pricing strategies, customer lists, or
         other subject matters pertaining to the business and/or financial
         affairs of the Corporation. "Confidential Information" shall not
         include any information that is in the public domain during the period
         of Executive's service to the Corporation other than as a result of
         disclosure by Executive in violation of this Agreement or any other
         agreement related to Executive's employment with the Corporation.

              b.   If Executive is required by a court of competent jurisdiction
         or other tribunal (by oral questions, interrogatories, requests for
         information or documents, subpoena, civil investigation demand or
         similar process) to disclose any Confidential Information, Executive
         may disclose such Information to such tribunal without liability
         hereunder, PROVIDED, THAT Executive first provides the Corporation with
         notice of any such


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         requirement(s) as promptly as practicable, but in any case with
         sufficient timeliness to enable the Corporation to seek an appropriate
         protective order and/or waive its compliance with the relevant
         provisions of this Agreement.

         5.   COVENANTS AGAINST COMPETITION.

              a.   In view of the unique value to the Corporation of the
         services of Executive and because of the Confidential Information to be
         obtained by or disclosed to Executive, as herein above set forth, and
         as a material inducement to the Corporation to enter into this
         Agreement and to pay to Executive the compensation and benefits set
         forth in this Agreement, Executive covenants and agrees that during
         Executive's employment and for a period of one year after he ceases to
         be employed by the Corporation for any reason (unless the termination
         of the Executive's employment by the Corporation is without cause), he
         will not, except as otherwise authorized by this Agreement, compete in
         the field of pharmacogenomics with the Corporation or any affiliate of
         the Corporation, solicit the Corporation's customers or the customers
         of any of its affiliates in the field of pharmacogenomics, or directly
         or indirectly solicit for employment any of the Corporation's
         employees.

              b.   For the purposes of this Agreement:

                   (i)       The term "compete" means engaging in the same or
              any similar business as the Corporation or any of its affiliates
              in any manner whatsoever, including without limitation as a
              proprietor, partner, investor, shareholder, member, director,
              officer, employee, consultant, independent contractor or
              otherwise, within any geographic area in which the Corporation's
              products are offered or distributed;

                   (ii)      The term "affiliate," when used in reference to any
              Person (as hereinafter defined), means any other Person that
              directly or indirectly through one or more intermediaries
              controls, is controlled by, or is under common control with the
              first such Person; and

                   (iii)     The term "customers" means all Persons to whom the
              Corporation or any of its affiliates has provided any product or
              service, whether or not for compensation, within a period of two
              (2) years prior to the time Executive ceases to be employed by the
              Corporation.

                   (iv)      The term "cause" means material misconduct by the
              Executive or substantially inadequate performance of his duties of
              employment.

              c.   None of the provisions of this Section 5 shall prohibit
         Executive from investing in securities listed on a national securities
         exchange or actively traded over-the-counter so long as such
         investments are not greater than five percent (5%) of the outstanding
         securities of any issuer of the same class or issue.


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         6.   REASONABLENESS OF RESTRICTIONS.

              a.   Executive has carefully read and considered the provisions of
         Section 4 and Section 5, and, having done so, agrees that:

                   (i)       The restrictions set forth in Section 4 and Section
              5, including but not limited to the time period, scope and
              geographical area of restriction, are fair and reasonable and are
              reasonably required for the protection of the good will and other
              legitimate business interests of the Corporation and its
              affiliates, officers, directors, shareholders, and other
              employees;

                   (ii)      Executive has received adequate consideration for
              such obligations; and

                   (iii)     Such obligations do not prevent Executive from
              earning a livelihood.

              b.   If, notwithstanding the foregoing, any of the provisions of
         Section 4 or Section 5 shall be held to be invalid or unenforceable,
         the remaining provisions thereof shall nevertheless continue to be
         valid and enforceable as though the invalid and unenforceable parts had
         not been included therein. If any provision of Section 4 or Section 5
         relating to the time period and/or the areas of restriction and/or
         related aspects shall be declared by a court of competent jurisdiction
         to exceed the maximum restrictiveness such court deems reasonable and
         enforceable, the time period and/or areas of restriction and/or related
         aspects deemed reasonable and enforceable by the court shall become and
         thereafter be the maximum restriction in such regard, and the
         restriction shall remain enforceable to the fullest extent deemed
         reasonable by such court.

         7.   REMEDIES FOR BREACH OF EXECUTIVE'S COVENANTS OF NON-DISCLOSURE AND
NON-COMPETITION. Executive recognizes and agrees that the Corporation's remedy
at law for any breach of Section 4 or Section 5 would be inadequate as such a
breach would cause irreparable harm to the Corporation, and he agrees that, for
breach of such provisions, the Corporation shall, in addition to such other
remedies as may be available to it at law or in equity, be entitled to
injunctive relief and to enforce its rights by an action for specific
performance.

         8.   WAIVER. A party's failure to insist on compliance or enforcement
of any provision of this Agreement shall not affect the validity or
enforceability or constitute a waiver of future enforcement of that provision or
of any other provision of this Agreement by that party or any other party.

         9.   GOVERNING LAW. This Agreement shall in all respects be subject to,
and governed by, the laws of the State of Connecticut.

         10.  SEVERABILITY. The invalidity or unenforceability of any provision
in the Agreement shall not in any way affect the validity or enforceability of
any other provision and


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this Agreement shall be construed in all respects as if such invalid or
unenforceable provision had never been in the Agreement.

         11.  NOTICE. Any and all notices required or permitted herein shall be
in writing and shall be deemed to have been duly given (a) when delivered if
delivered personally, (b) on the fifth day following the date of deposit in the
United States mail if sent first class, postage prepaid, by certified mail, or
(c) one day after delivery to a nationally recognized overnight courier service.
The parties' respective addresses for such notices shall be those set forth
following their respective signatures below, or such other address or addresses
as either party may hereafter designate in writing to the other.

         12.  ASSIGNMENT. This Agreement, together with any amendments hereto,
shall be binding upon and shall inure to the benefit of the parties hereto and
their respective successors, assigns, heirs, executors, and legal and personal
representatives, except that the rights and benefits of Executive under this
Agreement may not be assigned without the prior written consent of the
Corporation. Without limiting the generality of the foregoing, this Agreement
shall be binding upon and inure to the benefit of any corporation with which or
into which the Corporation or its successors may be merged or which may succeed
to its assets or business.

         13.  AMENDMENTS. This Agreement may be amended at any time by mutual
consent of the parties hereto, with any such amendment to be invalid unless in
writing and signed by the Corporation and Executive.

         14.  ENTIRE AGREEMENT. This Agreement contains the entire agreement and
understanding by and between Executive and the Corporation with respect to the
subject matter hereof and supersedes all existing agreements between the
Corporation and Executive with respect to such subject matter. No
representations, promises, agreements, or understandings, written or oral,
relating to the employment of Executive by the Corporation not contained herein
shall be of any force or effect.

         15.  REFERENCES TO GENDER AND NUMBER TERMS. In construing this
Agreement, feminine or number pronouns shall be substituted for those masculine
in form and vice versa, and plural terms shall be substituted for singular and
singular for plural in any place in which the context so requires.

         16.  COUNTERPARTS; HEADINGS; SECTIONS. This Agreement may be executed
in multiple counterparts, each of which shall be considered to have the force
and effect of any original but all of which taken together shall constitute but
one and the same instrument. The various headings in this Agreement are inserted
for convenience only and are not part of the Agreement. All references to
"Sections" and "paragraphs" in this Agreement refer to the various corresponding
sections and paragraphs of this Agreement.

         17.  SURVIVAL. The covenants and agreements contained in Sections 3
through 7 shall survive any termination of Executive's employment with the
Corporation.


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         18.  ARBITRATION. Executive and the Corporation will submit any
disputes arising under this Agreement to an arbitration panel conducting a
binding arbitration in Hartford, Connecticut, in accordance with the Commercial
Arbitration Rules of the American Arbitration Association in effect on the date
of such arbitration (the "Rules"), and judgment upon the award rendered by the
arbitrator or arbitrators may be entered in any court having jurisdiction
thereof; PROVIDED, HOWEVER, that nothing herein shall impair the Corporation's
right to seek equitable relief for breach or threatened breach of Section 4 or
Section 5. The award of the arbitrators shall be final and shall be the sole and
exclusive remedy between the parties regarding any claims, counterclaims, issue
or accounting presented to the arbitration panel. The parties hereto further
agree that the arbitration panel shall consist of one (1) person mutually
acceptable to the Corporation and Executive, PROVIDED that if the parties cannot
agree on an arbitrator within fifteen (15) days of filing a notice of
arbitration, the arbitration panel shall consist of three (3) persons, one
selected by the Corporation, one selected by Executive (or his representative)
and one selected by the arbitrators so selected by the parties hereto, or if the
parties hereto cannot agree, selected by the manager of the principal office of
the American Arbitration Association in Hartford County in the State of
Connecticut. All fees and expenses of the arbitration, including a transcript if
either party requests, shall be borne equally by the parties. Each party will
pay for the fees and expenses of its own attorneys, experts, witnesses, and
preparation and presentation of proofs and post-hearing briefs (unless the party
prevails on a claim for which attorney's fees are recoverable under the Rules).
Any action to enforce or vacate the arbitrator's award shall be governed by the
federal Arbitration Act, if applicable, and otherwise by applicable state law.
If either the Corporation or Executive pursues any claim, dispute or controversy
against the other in a proceeding other than the arbitration provided for
herein, the responding party shall be entitled to dismissal or injunctive relief
regarding such action and recovery of all costs, losses and attorney's fees
related to such action.


                       THE NEXT PAGE IS THE SIGNATURE PAGE


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         IN WITNESS WHEREOF, the Corporation and Executive have duly executed
this Agreement as of the day and year first above written.


                                  CORPORATION:

                                  GENAISSANCE PHARMACEUTICALS, INC.

                                  By:
                                     ------------------------------
                                     Name:
                                     Its

                                  Address for Notice Purposes:
                                  5 Science Park
                                  Suite 2103
                                  New Haven, CT 06511

                                  EXECUTIVE:


                                  ----------------------------------
                                  RICHARD JUDSON
                                  Address for Notice Purposes:
                                  42 Barker Hill Road
                                  Guilford, CT 06437


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