<PAGE>

   As filed with the Securities and Exchange Commission on October 21, 1999

                                                     REGISTRATION NO. 333-
===============================================================================



                                   FORM S-8

            REGISTRATION STATEMENT UNDER THE SECURITIES ACT OF 1933

                            ---------------------

                              CURAGEN CORPORATION
            (Exact name of registrant as specified in its charter)

            DELAWARE                                         06-1331400
  (State or other jurisdiction                           (I.R.S. Employer
of incorporation or organization)                       Identification No.)

                       555 LONG WHARF DRIVE, 11TH FLOOR
                         NEW HAVEN, CONNECTICUT  06511
           (Address of Principal Executive Offices) (Zip Code)

     CURAGEN CORPORATION 1997 EMPLOYEE, DIRECTOR AND CONSULTANT STOCK PLAN
                           (Full title of the plan)

                          JONATHAN M. ROTHBERG, Ph.D.
                     Chief Executive Officer, President and
                             Chairman of the Board
                              Curagen Corporation
                       555 Long Wharf Drive, 11th Floor
                          New Haven, Connecticut 06511
                    (Name and address of agent for service)

                                (203)-401-3330
                           (203)-401-3333 FACSIMILE
         (Telephone number, including area code, of agent for service)

                            ---------------------

                        CALCULATION OF REGISTRATION FEE

<TABLE>
<CAPTION>
--------------------------------------------------------------------------------------------------------------
                                                         Proposed           Proposed
  Title of                           Amount to be         maximum            Maximum             Amount of
securities to be registered          registered(1)    offering price        Aggregate         registration fee
                                                        per share(2)     Offering price(2)
--------------------------------------------------------------------------------------------------------------
<S>                                <C>               <C>                <C>                  <C>
Common Stock, $.01 par value          2,000,000          $14.375           $28,750,000             $7,993
                                      =========                                                     =====
--------------------------------------------------------------------------------------------------------------
</TABLE>
(1) The number of shares of common stock, par value $.01 per share ("Common
    Stock"), stated above consists of the aggregate number of additional shares
    not previously registered which may be sold upon the exercise of options
    which may hereafter be granted under the CuraGen Corporation 1997 Employee,
    Director and Consultant Stock Plan (the "Plan").  The maximum number of
    shares which may be sold upon the exercise of such options granted under the
    Plan is subject to adjustment in accordance with certain anti-dilution and
    other provisions of said Plan.  Accordingly, pursuant to Rule 416 under the
    Securities Act of 1933, as amended (the "Securities Act"), this Registration
    Statement covers, in addition to the number of shares stated above, an
    indeterminate number of shares which may be subject to grant or otherwise
    issuable after the operation of any such anti-dilution and other provisions.

(2) This calculation is made solely for the purpose of determining the
    registration fee pursuant to the provisions of Rule 457(h) under the
    Securities Act and is made on the basis of the average of the high and low
    sale prices per share of the Common Stock on the National Market System of
    the National Association of Securities Dealers Automated Quotation System
    (NASDAQ) as of a date (October 18, 1999) within 5 business days prior to
    filing this Registration Statement.

================================================================================
<PAGE>

                                 EXPLANATORY NOTE
                                 ----------------


     In accordance with the instructional Note to Part I of Form S-8 as
promulgated by the Securities and Exchange Commission, the information specified
by Part I of Form S-8 has been omitted from this Registration Statement on Form
S-8 for offers of Common Stock pursuant to the Plan.  This Registration
Statement on Form S-8 hereby registers 2,000,000 additional shares of Common
Stock pursuant to the Plan.  A Registration Statement on Form S-8 (File No. 333-
56829), registering an aggregate of 3,058,383 shares of Common Stock under (i)
the Plan, (ii) the CuraGen Corporation 1993 Stock Option and Incentive Award
Plan and (iii) certain Non-Qualified Stock Option Agreements was filed with the
Securities and Exchange Commission on June 15, 1998.
<PAGE>

                                    PART II

              INFORMATION REQUIRED IN THE REGISTRATION STATEMENT


Item 3.  Incorporation of Certain Documents by Reference.
--------------------------------------------------------

     The following documents filed by the Company with the Commission are
incorporated herein by reference:

     (a) The Company's Annual Report on Form 10-K for the fiscal year ended
December 31, 1998.

     (b) The Company's Quarterly Report on Form 10-Q for the quarter ended March
31, 1999.

     (c) The Company's Quarterly Report on Form 10-Q for the quarter ended June
30, 1999.

     (d) The Company's Current Report on Form 8-K filed on September 8, 1999.

     (e) The description of the Common Stock contained in the Company's
Registration Statement on Form 8-A, File No. 000-23223 filed under the
Securities Exchange Act of 1934, including any amendment or report filed for the
purpose of updating such description.

     All reports and other documents filed by the Registrant after the date
hereof pursuant to Sections 13(a), 13(c), 14 and 15(d) of the Securities
Exchange Act of 1934 prior to the filing of a post-effective amendment which
indicates that all securities offered hereby have been sold or which deregisters
all securities then remaining unsold, shall be deemed to be incorporated by
reference herein and to be part hereof from the date of filing of such reports
and documents.

Item 4.  Description of Securities.
----------------------------------

     Not applicable.

Item 5.  Interests of Named Experts and Counsel.
-----------------------------------------------

     The validity of the issuance of the shares of Common Stock registered under
this Registration Statement has been passed upon for the Company by Mintz,
Levin, Cohn, Ferris, Glovsky and Popeo, P.C. of Boston, Massachusetts.  Mintz,
Levin, Cohn, Ferris, Glovsky and Popeo, P.C., members of Mintz, Levin, Cohn,
Ferris, Glovsky and Popeo, P.C. and certain members of their families and trusts
for their benefit own an aggregate of approximately 51,452 shares of Common
Stock of the Company and warrants to purchase an aggregate of approximately
18,413 shares of Common Stock of the Company.

Item 6.  Indemnification of Directors and Officers.
--------------------------------------------------

     Incorporated herein by reference from the Company's Registration Statement
on Form S-1, File No. 333-38051.

                                      II-1
<PAGE>

Item 7.  Exemption from Registration Claimed.
--------------------------------------------

     Not applicable.

Item 8.  Exhibits.
-----------------

     (4.1)  Form of Common Stock Certificate (Filed as Exhibit 4.2 to the
            Registrant's Registration Statement on Form S-1, as amended, File
            No. 333-38051, and incorporated herein by reference).

     (4.2)  Article Fourth of the Amended and Restated Certificate of
            Incorporation of the Registrant (Filed as Exhibit 3.3 to the
            Registrant's Registration Statement on Form S-1, File No. 333-38051,
            and incorporated herein by reference).

     (4.3)  Amended and Restated Bylaws of the Registrant (Filed as Exhibit
            3.5 to the Registrant's Registration Statement on Form S-1, as
            amended, File No. 333-38051, and incorporated herein by reference).

     (5)    Opinion of Mintz, Levin, Cohn, Ferris, Glovsky and Popeo, P.C. as to
            the legality of shares being registered.

     (23.1) Consent of Mintz, Levin, Cohn, Ferris, Glovsky and Popeo, P.C.
            (included in opinion of counsel filed as Exhibit 5).

     (23.2) Consent of Deloitte & Touche LLP

     (24)   Power of Attorney to file future amendments (set forth on the
            signature page of this Registration Statement.)

     (99)   1997 Employee, Director and Consultant Stock Plan, as amended and
            restated through May 12, 1999.

Item 9.  Undertakings.
---------------------

(a)  The undersigned Registrant hereby undertakes:

     (1)    To file, during any period in which offers or sales are being made,
            a post-effective amendment to this Registration Statement:

               (i) To include any prospectus required by Section 10(a)(3) of the
                   Securities Act of 1933;

               (ii) To reflect in the prospectus any facts or events arising
                    after the effective date of the Registration Statement (or
                    the most recent post-effective amendment thereof) which,
                    individually or in the aggregate, represents a fundamental
                    change in the information set forth in the Registration
                    Statement. Notwithstanding the foregoing, any increase or
                    decrease in volume of securities offered (if the total
                    dollar value of securities offered would


                                      II-2
<PAGE>

          not exceed that which was registered) and any deviation from the low
          or high end of the estimated maximum offering range may be reflected
          in the form of prospectus filed with the Commission pursuant to Rule
          424(b) if, in the aggregate, the changes in volume and price represent
          no more than a 20% change in the maximum aggregate offering price set
          forth in the "Calculation of Registration Fee" table in the effective
          Registration Statement.

               (iii)  To include any material information with respect to the
          plan of distribution not previously disclosed in the Registration
          Statement or any material change to such information in the
          Registration Statement;

          Provided, however, that paragraphs (a)(1)(i) and (a)(1)(ii) do not
     apply if the Registration Statement is on Form S-3 or Form S-8, and the
     information required to be included in a post-effective amendment by those
     paragraphs is contained in periodic reports filed by the Registrant
     pursuant to Section 13 or Section 15(d) of the Securities Exchange Act of
     1934 that are incorporated by reference in the Registration Statement.

     (2) That, for the purpose of determining any liability under the Securities
     Act of 1933, each such post-effective amendment shall be deemed to be a new
     registration statement relating to the securities offered therein, and the
     offering of such securities at that time shall be deemed to be the initial
     bona fide offering thereof.

     (3) To remove from registration by means of a post-effective amendment any
     of the securities being registered which remain unsold at the termination
     of the offering.

(b)  The undersigned Registrant hereby undertakes that, for purposes of
     determining any liability under the Securities Act of 1933, each filing of
     the Registrant's annual report pursuant to Section 13(a) or Section 15(d)
     of the Securities Exchange Act of 1934 that is incorporated by reference in
     this Registration Statement shall be deemed to be a new registration
     statement relating to the securities offered therein, and the offering of
     such securities at that time shall be deemed to be the initial bona fide
     offering thereof.

(c)  Insofar as indemnification for liabilities arising under the Securities Act
     of 1933 may be permitted to directors, officers and controlling persons of
     the Registrant, the Registrant has been advised that in the opinion of the
     Securities and Exchange Commission such indemnification is against public
     policy as expressed in the Act and is, therefore, unenforceable.  In the
     event that a claim for indemnification against such liabilities (other than
     the payment by the Registrant of expenses incurred or paid by a director,
     officer or controlling person of the Registrant in the successful defense
     of any action, suit or proceeding) is asserted by such director, officer or
     controlling person in connection with the securities being registered, the
     Registrant will, unless in the opinion of its counsel the matter has been
     settled by controlling precedent, submit to a court of appropriate
     jurisdiction the question whether such indemnification by it is against
     public policy as expressed in the Act and will be governed by the final
     adjudication of such issue.

(d)  The undersigned registrant hereby undertakes to deliver or cause to be
     delivered with the prospectus, to each person to whom the prospectus is
     sent or given, the latest annual report to security holders that is
     incorporated by reference in the prospectus and furnished pursuant to and
     meeting the requirements of Rule 14a-3 or Rule 14c-3 under the Securities
     Exchange Act of 1934; and, where interim financial information required to
     be presented by Article 3 of Regulation S-X are not set forth in the
     prospectus, to deliver or cause to be delivered to each person to whom the
     prospectus is sent or given, the latest quarterly report that is
     specifically incorporated by reference in the prospectus to provide such
     interim financial information.

                                      II-3
<PAGE>

                                 SIGNATURES

     The Registrant.  Pursuant to the requirements of the Securities Act of
1933, the Registrant certifies that it has reasonable grounds to believe that it
meets all of the requirements for filing on Form S-8 and has duly caused this
Registration Statement to be signed on its behalf by the undersigned, thereunto
duly authorized, in the City of New Haven, Connecticut on this 21st day of
October, 1999


                                    CURAGEN CORPORATION



                                    By /s/ Jonathan M. Rothberg
                                      ----------------------------------------
                                      Jonathan M. Rothberg
                                      Chief Executive Officer, President and
                                      Chairman of the Board


     Each person whose signature appears below constitutes and appoints Jonathan
M. Rothberg his true and lawful attorney-in-fact and agent, with full power of
substitution and resubstitution, for him and in his name, place and stead, and
in any and all capacities, to sign any and all amendments (including post-
effective amendments) to this Registration Statement on Form S-8 of CuraGen
Corporation, and to file the same, with all exhibits thereto and other documents
in connection therewith, with the Securities and Exchange Commission, granting
unto said attorney-in-fact and agent full power and authority to do and perform
each and every act and thing requisite or necessary to be done in or about the
premises, as full to all intents and purposes as he might or could do in person,
hereby ratifying and confirming all that said attorney-in-fact and agent or his
substitute or substitutes may lawfully do or cause to be done by virtue hereof.

     Pursuant to the requirements of the Securities Act of 1933, this
Registration Statement  has been signed by the following persons in the
capacities and on the dates indicated.

Signature                           Title                   Date
---------                           -----                   ----


/s/ Jonathan M. Rothberg    Chief Executive Officer,        October 21, 1999
------------------------    President and Chairman
Jonathan M. Rothberg        of the Board
                            (principal executive officer)


/s/ David M. Wurzer         Executive Vice President,       October 21, 1999
------------------------    Treasurer and Chief Financial
David M. Wurzer             Officer (principal financial
                            and accounting officer)

                                      II-4
<PAGE>

/s/ Vincent T. DeVita, M.D.      Director                    October 21, 1999
--------------------------
Vincent T. DeVita, M.D.

/s/ Richard H. Booth             Director                    October 21, 1999
--------------------------
Richard H. Booth

/s/ Robert E. Patricelli         Director                    October 21, 1999
--------------------------
Robert E. Patricelli

/s/ James L. Vincent             Director                    October 21, 1999
--------------------------
James L. Vincent

                                      II-5
<PAGE>

                              CURAGEN CORPORATION

                         INDEX TO EXHIBITS FILED WITH
                        FORM S-8 REGISTRATION STATEMENT

     (4.1)  Form of Common Stock Certificate (Filed as Exhibit 4.2 to the
            Registrant's Registration Statement on Form S-1, as amended, File
            No. 333-38051, and incorporated herein by reference).

     (4.2)  Article Fourth of the Amended and Restated Certificate of
            Incorporation of the Registrant (Filed as Exhibit 3.3 to the
            Registrant's Registration Statement on Form S-1, File No. 333-38051,
            and incorporated herein by reference).

     (4.3)  Amended and Restated Bylaws of the Registrant (Filed as Exhibit
            3.5 to the Registrant's Registration Statement on Form S-1, as
            amended, File No. 333-38051, and incorporated herein by reference).

     (5)    Opinion of Mintz, Levin, Cohn, Ferris, Glovsky and Popeo, P.C. as to
            the legality of shares being registered.

     (23.1) Consent of Mintz, Levin, Cohn, Ferris, Glovsky and Popeo, P.C.
            (included in opinion of counsel filed as Exhibit 5).

     (23.2) Consent of Deloitte & Touche LLP

     (24)   Power of Attorney to file future amendments (set forth on the
            signature page of this Registration Statement.)

     (99)   1997 Employee, Director and Consultant Stock Plan, as amended and
            restated through May 12, 1999.

                                      II-6