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                                  Exhibit 4.2

                     Resale Registration Rights Agreement

                                    between

                              CuraGen Corporation

                                      and

                             Lehman Brothers Inc.,

                       Morgan Stanley & Co. Incorporated

                                      and

                          Dain Rauscher Incorporated





                         Dated as of February 2, 2000
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          Resale Registration Rights Agreement, dated as of February 2, 2000
between CuraGen Corporation, a Delaware corporation (together with any successor
entity, herein referred to as the "Company"), and Lehman Brothers Inc., Morgan
Stanley & Co. Incorporated and Dain Rauscher Incorporated (collectively, the
"Initial Purchasers").

          Pursuant to the Purchase Agreement, dated January 27, 2000, between
the Company and the Initial Purchasers (the "Purchase Agreement"), the Initial
Purchasers have agreed to purchase from the Company up to $125,000,000
($150,000,000 if the Initial Purchasers exercise the over-allotment option in
full) in aggregate principal amount of the Company's 6.00% Convertible
Subordinated Debentures due 2007 (the "Debentures").  The Debentures will be
convertible into fully paid, nonassessable shares of common stock, par value
$0.01 per share, of the Company  (the "Common Stock") on the terms, and subject
to the conditions, set forth in the Indenture (as defined herein).  To induce
the Initial Purchasers to purchase the Debentures, the Company has agreed to
provide the registration rights set forth in this Agreement pursuant to Section
3(j) of the Purchase Agreement.

          The parties hereby agree as follows:

          1. Definitions. As used in this Agreement, the following capitalized
terms shall have the following meanings:

          Advice:  As defined in Section 4(c)(ii) hereof.

          Additional Amounts:  As defined in Section 3(a) hereof.

          Affiliate:  As such term is defined in Rule 405 under the Securities
     Act.

          Agreement:  This Resale Registration Rights Agreement.

          Blue Sky Application:  As defined in Section 6(a) hereof.

          Broker-Dealer:  Any broker or dealer registered under the Exchange
     Act.

          Business Day:  A day other than a Saturday or Sunday or any federal
     holiday in the United States.

          Closing Date:  The date of this Agreement.

          Commission:  Securities and Exchange Commission.

          Common Stock:  As defined in the preamble hereto.

          Damages Payment Date:  Each Interest Payment Date.  For purposes of
     this Agreement, if no Debentures are outstanding, "Damages Payment Date"
     shall mean each August 2 and February 2.

          Debentures:  As defined in the preamble hereto.

          Effectiveness Period:  As defined in Section 2(a)(iii) hereof.

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          Effectiveness Target Date:  As defined in Section 2(a)(ii) hereof.

          Exchange Act:  Securities Exchange Act of 1934, as amended.

          Holder:  A Person who owns, beneficially or otherwise, Transfer
     Restricted Securities.

          Indemnified Holder:  As defined in Section 6(a) hereof.

          Indenture:  The Indenture, dated as of February 2, 2000, between the
     Company and The Chase Manhattan Bank, as trustee (the "Trustee"), pursuant
     to which the Debentures are to be issued, as such Indenture is amended,
     modified or supplemented from time to time in accordance with the terms
     thereof.

          Initial Purchasers:  As defined in the preamble hereto.

          Interest Payment Date:  As defined in the Indenture.

          Company:  As defined in the preamble hereto.

          Majority of Holders:  Holders holding 50% in aggregate principal
     amount of the Debentures outstanding at the time of determination of the
     Majority of Holders; provided, however, that, for purposes of this
     definition, a holder of shares of Common Stock which constitute Transfer
     Restricted Securities that were previously issued upon conversion of
     Debentures shall be deemed to hold an aggregate principal amount of
     Debentures (in addition to the principal amount of Debentures held by such
     holder) equal to the product of (x) the number of such shares of Common
     Stock held by such holder and (y) the prevailing conversion price, such
     prevailing conversion price as determined in accordance with Section 12 of
     the Indenture.

          NASD:  National Association of Securities Dealers, Inc.

          Person:  An individual, partnership, corporation, unincorporated
     organization, trust, joint venture or a government or agency or political
     subdivision thereof.

          Prospectus:  The prospectus included in a Shelf Registration
     Statement, as amended or supplemented by any prospectus supplement and by
     all other amendments thereto, including post-effective amendments, and all
     material incorporated by reference into such Prospectus.

          Questionnaire Deadline:  As defined in Section 2(b) hereof.

          Record Holder:  With respect to any Damages Payment Date, each Person
     who is a Holder on the record date with respect to the Interest Payment
     Date on which such Damages Payment Date shall occur.  In the case of a
     Holder of shares of Common Stock issued upon conversion of the Debentures,
     "Record Holder" shall mean each Person who is a Holder of shares of Common
     Stock which constitute Transfer Restricted Securities on the July 19 or
     February 19 immediately preceding the Damages Payment Date.

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          Registration Default:  As defined in Section 3(a) hereof.

          Sale Notice:  As defined in Section 4(e) hereof.

          Securities Act:  Securities Act of 1933, as amended.

          Shelf Filing Deadline: As defined in Section 2(a)(i) hereof.

          Shelf Registration Statement:  As defined in Section 2(a)(i) hereof.

          Suspension Period.  As defined in Section 4(b)(i) hereof.

          TIA:  Trust Indenture Act of 1939, as in effect on the date the
     Indenture is qualified under the TIA.

          Transfer Restricted Securities:  Each Debenture and each share of
     Common Stock issued upon conversion of Debentures until the earliest to
     occur of:

             (i)   the date on which such Debenture or such share of Common
          Stock issued upon conversion has been effectively registered under the
          Securities Act and disposed of in accordance with the Shelf
          Registration Statement;

             (ii)  the date on which such Debenture or such share of Common
          Stock issued upon conversion (A) has been transferred in compliance
          with Rule 144 under the Securities Act or (B) may be sold or
          transferred pursuant to Rule 144 under the Securities Act without
          regard to the volume limitations thereof (or any other similar
          provision then in force); and

             (iii) the date on which such Debenture or such share of Common
          Stock issued upon conversion ceases to be outstanding (whether as a
          result of redemption, repurchase and cancellation, conversion or
          otherwise).

          Underwritten Registration or Underwritten Offering:  A registration in
     which securities of the Company are sold to an underwriter for reoffering
     to the public.

     2.   Shelf Registration.

     (a)  The Company shall:

             (i)   not later than 90 days after the earliest date of original
          issuance of any of the Debentures (the "Shelf Filing Deadline"), cause
          a registration statement to be filed pursuant to Rule 415 under the
          Securities Act (the "Shelf Registration Statement"), which Shelf
          Registration Statement shall provide for resales of all Transfer
          Restricted Securities held by Holders that have provided the
          information required pursuant to the terms of Section 2(b) hereof;

             (ii)    use its reasonable efforts to cause the Shelf Registration
          Statement to be declared effective by the Commission as promptly as is
          practicable but in no

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     event later than 180 days after the earliest date of original issuance of
     any of the Debentures (the "Effectiveness Target Date"); and

              (iii)  use its reasonable efforts to keep the Shelf Registration
     Statement continuously effective, supplemented and amended as required by
     the provisions of Section 4(b) hereof to the extent necessary to ensure
     that: (A) it is available for resales by the Holders of Transfer Restricted
     Securities entitled to the benefit of this Agreement and (B) conforms with
     the requirements of this Agreement and the Securities Act and the rules and
     regulations of the Commission promulgated thereunder as announced from time
     to time, for a period (the "Effectiveness Period") of:

                         (1) two years following the last date of original
                    issuance of Debentures; or

                         (2) such shorter period that will terminate when (x)
                    all of the Holders of Transfer Restricted Securities (other
                    than the Company and its Affiliates) are able to sell all
                    Transfer Restricted Securities without restriction pursuant
                    to the volume limitation provisions of Rule 144 under the
                    Securities Act or any successor rule thereto, (y) when all
                    Transfer Restricted Securities have ceased to be outstanding
                    (whether as a result of redemption, repurchase and
                    cancellation, conversion or otherwise) or (z) all Transfer
                    Restricted Securities registered under the Shelf
                    Registration Statement have been sold.

     (b) No Holder of Transfer Restricted Securities may include any of its
Transfer Restricted Securities in the Shelf Registration Statement pursuant to
this Agreement unless such Holder furnishes to the Company in writing, prior to
or on the 20th Business Day after receipt of a request therefor (the
"Questionnaire Deadline"), such information as the Company may reasonably
request for use in connection with the Shelf Registration Statement or
Prospectus or preliminary Prospectus included therein and in any application to
be filed with or under state securities laws.  In connection with all such
requests for information from Holders of Transfer Restricted Securities, the
Company shall notify such Holders of the requirements set forth in the preceding
sentence.  No Holder of Transfer Restricted Securities shall be entitled to
Additional Amounts pursuant to Section 3 hereof unless such Holder shall have
provided all such reasonably requested information prior to or on the
Questionnaire Deadline.  Each Holder as to which the Shelf Registration
Statement is being effected agrees to furnish promptly to the Company all
information required to be disclosed in order to make information previously
furnished to the Company by such Holder not materially misleading.

     3.  Additional Amounts.

     (a) If:

             (i)   the Shelf Registration Statement is not filed with the
     Commission prior to or on the Shelf Filing Deadline;

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             (ii)  the Shelf Registration Statement has not been declared
     effective by the Commission prior to or on the Effective Target Date;

             (iii) subject to the provisions of Section 4(b)(i) hereof, the
     Shelf Registration Statement is filed and declared effective but, during
     the Effectiveness Period, shall thereafter cease to be effective or fail to
     be usable for its intended purpose without being succeeded within five
     Business Days by a post-effective amendment to the Shelf Registration
     Statement or a report filed with the Commission pursuant to Section 13(a),
     13(c), 14 or 15(d) of the Exchange Act that cures such failure and, in the
     case of a post-effective amendment, is itself immediately declared
     effective; or

             (iv)  prior to or on the 45/th/ or 60/th/ day, as the case may be,
     of any Suspension Period, such suspension has not been terminated,

(each such event referred to in foregoing clauses (i) through (iv), a
"Registration Default"), the Company hereby agrees to pay the following
additional amounts ("Additional Amounts") with respect to the Transfer
Restricted Securities from and including the day following the Registration
Default to but excluding the day on which the Registration Default has been
cured:

                   (A) in respect of the Debentures, to each holder of
             Debentures, (x) with respect to the first 90-day period during
             which a Registration Default shall have occurred and be continuing,
             in an amount per year equal to an additional 0.25% of the principal
             amount of the Debentures, and (y) with respect to the period
             commencing on the 91/st/ day following the day the Registration
             Default shall have occurred and be continuing, in an amount per
             year equal to an additional 0.50% of the principal amount of the
             Debentures; provided that in no event shall Additional Amounts
             accrue at a rate per year exceeding 0.50% of the principal amount
             of the Debentures; and

                   (B) in respect of any shares of Common Stock issued upon
             conversion of Debentures, to each holder of such shares of Common
             Stock, (x) with respect to the first 90-day period in which a
             Registration Default shall have occurred and be continuing, in an
             amount per year equal to 0.25% of the principal amount of the
             Debentures converted into such shares of Common Stock, and (y) with
             respect to the period commencing the 91/st/ day following the day
             the Registration Default shall have occurred and be continuing, in
             an amount per year equal to 0.50% of the principal amount of the
             Debentures converted into such shares of Common Stock; provided,
             however, that in no event shall Additional Amounts accrue at a rate
             per year exceeding 0.50% of the principal amount of the Debentures
             converted into such shares of Common Stock.

     (b) All accrued Additional Amounts shall be paid in arrears to Record
Holders by the Company on each Damages Payment Date by wire transfer of
immediately available funds.  Following the cure of all Registration Defaults
relating to any particular Debenture or share of

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Common Stock issued upon conversion of Debentures, the accrual of Additional
Amounts with respect to such Debenture or such share of Common Stock shall
cease.

          All obligations of the Company set forth in this Section 3 with
respect to any Transfer Restricted Security at the time such security ceases to
be a Transfer Restricted Security shall survive until such time as all such
obligations with respect to such Transfer Restricted Security shall have been
satisfied in full.

          The Additional Amounts set forth above shall be the exclusive monetary
remedy available to the Holders of Transfer Restricted Securities for
Registration Defaults.

          4.  Registration Procedures.

          (a) In connection with the Shelf Registration Statement, the Company
shall comply with all the provisions of Section 4(b) hereof and shall use its
reasonable efforts to effect such registration to permit the sale of the
Transfer Restricted Securities being sold in accordance with the intended method
or methods of distribution thereof, and pursuant thereto, shall as expeditiously
as possible prepare and file with the Commission a Shelf Registration Statement
relating to the registration on any appropriate form under the Securities Act.

          (b) In connection with the Shelf Registration Statement and any
Prospectus required by this Agreement to permit the sale or resale of Transfer
Restricted Securities, the Company shall:

               (i) Subject to any notice by the Company in accordance with this
          Section 4(b) of the existence of any fact or event of the kind
          described in Section 4(b)(iii)(D), use its reasonable efforts to keep
          the Shelf Registration Statement continuously effective during the
          Effectiveness Period; upon the occurrence of any event that would
          cause any the Shelf Registration Statement or the Prospectus contained
          therein (A) to contain a material misstatement or omission or (B) not
          be effective and usable for the resale of Transfer Restricted
          Securities during the Effectiveness Period, the Company shall file
          promptly an appropriate amendment to the Shelf Registration Statement
          or a report filed with the Commission pursuant to Section 13(a),
          13(c), 14 or 15(d) of the Exchange Act, in the case of clause (A),
          correcting any such misstatement or omission, and, in the case of
          either clause (A) or (B), use its reasonable efforts to cause such
          amendment to be declared effective and the Shelf Registration
          Statement and the related Prospectus to become usable for their
          intended purposes as soon as practicable thereafter. Notwithstanding
          the foregoing, the Company may suspend the effectiveness of the Shelf
          Registration Statement by written notice to the Holders for a period
          not to exceed an aggregate of 45 days in any 90-day period (each such
          period, a "Suspension Period") if:

                   (x) an event occurs and is continuing as a result of which
               the Shelf Registration Statement would, in the Company's
               reasonable judgment, contain an untrue statement of a material
               fact or omit to state a material fact required to be stated
               therein or necessary to make the statements therein not
               misleading; and

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                   (y) the Company reasonably determines that the disclosure of
               such event at such time would have a material adverse effect on
               the business of the Company (and its subsidiaries, if any, taken
               as a whole);

          provided, however, that in the event the disclosure relates to a
          previously undisclosed proposed or pending material business
          transaction, the disclosure of which would impede the Company's
          ability to consummate such transaction, the Company may extend a
          Suspension Period from 45 days to 60 days; provided, however, that
          Suspension Periods shall not exceed an aggregate of 90 days in any
          360-day period.

             (ii)  Prepare and file with the Commission such amendments and
          post-effective amendments to the Shelf Registration Statement as may
          be necessary to keep the Shelf Registration Statement effective during
          the Effectiveness Period; cause the Prospectus to be supplemented by
          any required Prospectus supplement, and as so supplemented to be filed
          pursuant to Rule 424 under the Securities Act, and to comply fully
          with the applicable provisions of Rules 424 and 430A under the
          Securities Act in a timely manner; and comply with the provisions of
          the Securities Act with respect to the disposition of all securities
          covered by the Shelf Registration Statement during the applicable
          period in accordance with the intended method or methods of
          distribution by the sellers thereof set forth in the Shelf
          Registration Statement or supplement to the Prospectus.

             (iii) Advise the underwriter(s), if any, and selling Holders
          promptly (but in any event within five Business Days) and, if
          requested by such Persons, to confirm such advice in writing:

                   (A) when the Prospectus or any Prospectus supplement or post-
             effective amendment has been filed, and, with respect to the Shelf
             Registration Statement or any post-effective amendment thereto,
             when the same has become effective,

                   (B) of any request by the Commission for amendments to the
             Shelf Registration Statement or amendments or supplements to the
             Prospectus or for additional information relating thereto,

                   (C) of the issuance by the Commission of any stop order
             suspending the effectiveness of the Shelf Registration Statement
             under the Securities Act or of the suspension by any state
             securities commission of the qualification of the Transfer
             Restricted Securities for offering or sale in any jurisdiction, or
             the initiation of any proceeding for any of the preceding purposes,
             or

                   (D) of the existence of any fact or the happening of any
             event, during the Effectiveness Period, that makes any statement of
             a material fact made in the Shelf Registration Statement, the
             Prospectus, any amendment or supplement thereto, or any document
             incorporated by

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             reference therein untrue, or that requires the making of any
             additions to or changes in the Shelf Registration Statement or the
             Prospectus in order to make the statements therein not misleading.

             (iv) If at any time the Commission shall issue any stop order
          suspending the effectiveness of the Shelf Registration Statement, or
          any state securities commission or other regulatory authority shall
          issue an order suspending the qualification or exemption from
          qualification of the Transfer Restricted Securities under state
          securities or Blue Sky laws, use its reasonable efforts to obtain the
          withdrawal or lifting of such order at the earliest possible time.

             (v)  Furnish to each of the selling Holders and each of the
          underwriter(s), if any, before filing with the Commission, a copy of
          the Shelf Registration Statement and copies of any Prospectus included
          therein or any amendments or supplements to the Shelf Registration
          Statement or Prospectus (other than documents incorporated by
          reference after the initial filing of the Shelf Registration
          Statement), which documents will be subject to the review of such
          Holders and underwriter(s), if any, for a period of at least ten
          Business Days, and the Company will not file the Shelf Registration
          Statement or Prospectus or any amendment or supplement to the Shelf
          Registration Statement or Prospectus (other than documents
          incorporated by reference) to which a selling Holder of Transfer
          Restricted Securities covered by the Shelf Registration Statement or
          the underwriter(s), if any, shall reasonably object within five
          Business Days after the receipt thereof.  A selling Holder or
          underwriter, if any, shall be deemed to have reasonably objected to
          such filing if the Shelf Registration Statement, amendment, Prospectus
          or supplement, as applicable, as proposed to be filed, contains a
          material misstatement or omission.

             (vi) Make available at reasonable times for inspection by one or
          more representatives of the selling Holders, designated in writing by
          a Majority of Holders whose Transfer Restricted Securities are
          included in the Shelf Registration Statement, any underwriter
          participating in any distribution pursuant to the Shelf Registration
          Statement, and any attorney or accountant retained by such selling
          Holders or any of the underwriter(s), all financial and other records,
          pertinent corporate documents and properties of the Company as shall
          be reasonably necessary to enable them to exercise any applicable due
          diligence responsibilities, and cause the Company's officers,
          directors, managers and employees to supply all information reasonably
          requested by any such representative or representatives of the selling
          Holders, underwriter, attorney or accountant in connection with the
          Shelf Registration Statement after the filing thereof and before its
          effectiveness; provided, however, that any information designated by
          the Company as confidential at the time of delivery of such
          information shall be kept confidential by the recipient thereof.

             (vii)  If reasonably requested by any selling Holders or the
          underwriter(s), if any, promptly incorporate in the Shelf Registration
          Statement or

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          Prospectus, pursuant to a supplement or post-effective amendment if
          necessary, such information as such selling Holders and
          underwriter(s), if any, may request to have included therein,
          including, without limitation: (A) information relating to the "Plan
          of Distribution" of the Transfer Restricted Securities, (B)
          information with respect to the principal amount of Debentures or
          number of shares of Common Stock being sold to such underwriter(s),
          (C) the purchase price being paid therefor and (D) any other terms of
          the offering of the Transfer Restricted Securities to be sold in such
          offering; provided, however, that with respect to any information
          requested for inclusion by a selling Holder, this clause (vii) shall
          apply only to such information that relates to the Transfer Restricted
          Securities to be sold by such selling Holder; and make all required
          filings of such Prospectus supplement or post-effective amendment as
          soon as reasonably practicable after the Company is notified of the
          matters to be incorporated in such Prospectus supplement or post-
          effective amendment.

             (viii)  Furnish to each selling Holder and each of the
          underwriter(s), if any, without charge, at least one copy of the Shelf
          Registration Statement, as first filed with the Commission, and of
          each amendment thereto (and any documents incorporated by reference
          therein or exhibits thereto (or exhibits incorporated in such exhibits
          by reference) as such Person may request).

             (ix)    Deliver to each selling Holder and each of the
          underwriter(s), if any, without charge, as many copies of the
          Prospectus (including each preliminary prospectus) and any amendment
          or supplement thereto as such Persons reasonably may request; subject
          to any notice by the Company in accordance with this Section 4(b) of
          the existence of any fact or event of the kind described in Section
          4(b)(iii)(D), the Company hereby consents to the use of the Prospectus
          and any amendment or supplement thereto by each of the selling Holders
          and each of the underwriter(s), if any, in connection with the
          offering and the sale of the Transfer Restricted Securities covered by
          the Prospectus or any amendment or supplement thereto.

             (x)     If  an underwriting agreement is entered into and the
          registration is an Underwritten Registration, the Company shall:

                     (A) upon request, furnish to each selling Holder and each
             underwriter, if any, in such substance and scope as they may
             reasonably request and as are customarily made by issuers to
             underwriters in primary underwritten offerings, upon the date of
             closing of any sale of Transfer Restricted Securities in an
             Underwritten Registration:

                         (1) a certificate, dated the date of such closing,
                     signed by the Chief Financial Officer of the Company
                     confirming, as of the date thereof, the matters set forth
                     in Section 5(g) of the Purchase Agreement and such other
                     matters as such parties may reasonably request;

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                         (2) opinions, each dated the date of such closing, of
                     counsel to the Company covering such of the matters as are
                     customarily covered in legal opinions to underwriters in
                     connection with primary underwritten offerings of
                     securities; and

                         (3) customary comfort letters, dated the date of such
                     closing, from the Company's independent accountants (and
                     from any other accountants whose report is contained or
                     incorporated by reference in the Shelf Registration
                     Statement), in the customary form and covering matters of
                     the type customarily covered in comfort letters to
                     underwriters in connection with primary underwritten
                     offerings of securities;

                     (B) set forth in full in the underwriting agreement, if
             any, indemnification provisions and procedures which provide rights
             no less protective than those set forth in Section 6 hereof with
             respect to all parties to be indemnified; and

                     (C) deliver such other documents and certificates as may be
             reasonably requested by such parties to evidence compliance with
             clause (A) above and with any customary conditions contained in the
             underwriting agreement or other agreement entered into by the
             selling Holders pursuant to this clause (x).

             (xi)    Before any public offering of Transfer Restricted
     Securities, cooperate with the selling Holders, the underwriter(s), if any,
     and their respective counsel in connection with the registration and
     qualification of the Transfer Restricted Securities under the securities or
     Blue Sky laws of such jurisdictions as the selling Holders or
     underwriter(s), if any, may reasonably request and do any and all other
     acts or things necessary or advisable to enable the disposition in such
     jurisdictions of the Transfer Restricted Securities covered by the Shelf
     Registration Statement; provided, however, that the Company shall not be
     required (A) to register or qualify as a foreign corporation or a dealer of
     securities where it is not now so qualified or to take any action that
     would subject it to the service of process in any jurisdiction where it is
     not now so subject or (B) to subject themselves to taxation in any such
     jurisdiction if they are not now so subject.

             (xii)   Cooperate with the selling Holders and the underwriter(s),
      if any, to facilitate the timely preparation and delivery of certificates
      representing Transfer Restricted Securities to be sold and not bearing any
      restrictive legends (unless required by applicable securities laws) and
      enable such Transfer Restricted Securities to be in such denominations and
      registered in such names as the Holders or the underwriter(s), if any, may
      request at least two Business Days before any sale of Transfer Restricted
      Securities made by such underwriter(s).

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             (xiii)  Use its reasonable efforts to cause the Transfer Restricted
      Securities covered by the Shelf Registration Statement to be registered
      with or approved by such other U.S. governmental agencies or authorities
      as may be necessary to enable the seller or sellers thereof or the
      underwriter(s), if any, to consummate the disposition of such Transfer
      Restricted Securities.

             (xiv)   Subject to Section 4(b)(i) hereof, if any fact or event
      contemplated by Section 4(b)(iii)(D) hereof shall exist or have occurred,
      use its reasonable efforts to prepare a supplement or post-effective
      amendment to the Shelf Registration Statement or related Prospectus or any
      document incorporated therein by reference or file any other required
      document so that, as thereafter delivered to the purchasers of Transfer
      Restricted Securities, the Prospectus will not contain an untrue statement
      of a material fact or omit to state any material fact required to be
      stated therein or necessary to make the statements therein not misleading.

             (xv)    Provide CUSIP numbers for all Transfer Restricted
      Securities not later than the effective date of the Shelf Registration
      Statement and provide the Trustee under the Indenture with certificates
      for the Debentures that are in a form eligible for deposit with The
      Depository Trust Company.

             (xvi)   Cooperate and assist in any filings required to be made
      with the NASD and in the performance of any due diligence investigation by
      any underwriter that is required to be retained in accordance with the
      rules and regulations of the NASD.

             (xvii)  Otherwise use its best efforts to comply with all
      applicable rules and regulations of the Commission and all reporting
      requirements under the rules and regulations of the Exchange Act.

             (xviii) Cause the Indenture to be qualified under the TIA not
      later than the effective date of the Shelf Registration Statement required
      by this Agreement, and, in connection therewith, cooperate with the
      Trustee and the holders of Debentures to effect such changes to the
      Indenture as may be required for such Indenture to be so qualified in
      accordance with the terms of the TIA, and execute and use its reasonable
      efforts to cause the Trustee thereunder to execute all documents that may
      be required to effect such changes and all other forms and documents
      required to be filed with the Commission to enable such Indenture to be so
      qualified in a timely manner.

             (xix)   Cause all Transfer Restricted Securities covered by the
      Shelf Registration Statement to be listed or quoted, as the case may be,
      on each securities exchange or automated quotation system on which similar
      securities issued by the Company are then listed or quoted.

             (xx)    Provide promptly to each Holder upon written request each
      document filed with the Commission pursuant to the requirements of Section
      13

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      and Section 15 of the Exchange Act after the effective date of the Shelf
      Registration Statement.

             (xxi)   If reasonably requested by the underwriters, make
      appropriate officers of the Company reasonably available to the
      underwriters for meetings with prospective purchasers of the Transfer
      Restricted Securities and prepare and present to potential investors
      customary "road show" material in a manner consistent with other new
      issuances of other securities similar to the Transfer Restricted
      Securities.

      (c) Each Holder agrees by acquisition of a Transfer Restricted Security
that, upon receipt of any notice from the Company of the existence of any fact
of the kind described in Section 4(b)(iii)(D) hereof, such Holder will, and will
use its reasonable efforts to cause any underwriter(s) in an Underwritten
Offering to, forthwith discontinue disposition of Transfer Restricted Securities
pursuant to the Shelf Registration Statement until:

             (i)  such Holder has received copies of the supplemented or amended
          Prospectus contemplated by Section 4(b)(xv) hereof; or

             (ii) such Holder is advised in writing (the "Advice") by the
          Company that the use of the Prospectus may be resumed, and has
          received copies of any additional or supplemental filings that are
          incorporated by reference in the Prospectus.

If so directed by the Company, each Holder will deliver to the Company (at the
Company's expense) all copies, other than permanent file copies then in such
Holder's possession, of the Prospectus covering such Transfer Restricted
Securities that was current at the time of receipt of such notice of suspension.

      (d) Each Holder who intends to be named as a selling Holder in the Shelf
Registration Statement shall furnish to the Company in writing, within 20
Business Days after receipt of a request therefor as set forth in a
questionnaire, such information regarding such Holder and the proposed
distribution by such Holder of its Transfer Restricted Securities as the Company
may reasonably request for use in connection with the Shelf Registration
Statement or Prospectus or preliminary Prospectus included therein.  (The form
of the questionnaire is attached hereto as Exhibit A.)  Holders that do not
complete the questionnaire and deliver it to the Company shall not be named as
selling securityholders in the Prospectus or preliminary Prospectus included in
the Shelf Registration Statement and therefore shall not be permitted to sell
any Transfer Restricted Securities pursuant to the Shelf Registration Statement.
Each Holder who intends to be named as a selling Holder in the Shelf
Registration Statement shall promptly furnish to the Company in writing such
other information as the Company may from time to time reasonably request in
writing.

      (e) Upon the effectiveness of the Shelf Registration Statement, each
Holder shall notify the Company at least three Business Days prior to any
intended distribution of Transfer Restricted Securities pursuant to the Shelf
Registration Statement (a "Sale Notice"), which notice

                                       12
<PAGE>

shall be effective for five Business Days. Each Holder of this Security, by
accepting the same, agrees to hold any communication by the Company in response
to a Sale Notice in confidence.

      5.  Registration Expenses.

     (a)  All expenses incident to the Company's performance of or compliance
with this Agreement shall be borne by the Company regardless of whether a Shelf
Registration Statement becomes effective, including, without limitation:

             (i)   all registration and filing fees and expenses (including
     filings made by any Initial Purchasers or Holders with the NASD);

             (ii)  all fees and expenses of compliance with federal securities
     and state Blue Sky or securities laws;

             (iii) all expenses of printing (including printing of Prospectuses
     and certificates for the Common Stock to be issued upon conversion of the
     Debentures), messenger and delivery services and telephone;

             (iv)  all fees and disbursements of counsel to the Company and,
     subject to Section 5(b) below, the Holders of Transfer Restricted
     Securities;

             (v)   all application and filing fees in connection with listing
     (or authorizing for quotation) the Common Stock on a national securities
     exchange or automated quotation system pursuant to the requirements hereof;
     and

             (vi)  all fees and disbursements of independent certified public
     accountants of the Company (including the expenses of any special audit and
     comfort letters required by or incident to such performance).

     The Company shall bear its internal expenses (including, without
limitation, all salaries and expenses of its officers and employees performing
legal, accounting or other duties), the expenses of any annual audit and the
fees and expenses of any Person, including special experts, retained by the
Company.

     (b) In connection with the Shelf Registration Statement required by this
Agreement, the Company shall reimburse the Initial Purchasers and the Holders of
Transfer Restricted Securities being registered pursuant to the Shelf
Registration Statement, as applicable, for the reasonable fees and disbursements
of not more than one counsel (which fees shall be subject to a maximum amount to
be mutually agreed upon among the Company, the Initial Purchasers and the
Holders of Transfer Restricted Securities), which shall be Cleary,  Gottlieb,
Steen & Hamilton, or such other counsel as may be chosen by a Majority of
Holders for whose benefit the Shelf Registration Statement is being prepared.

     6.  Indemnification and Contribution.

     (a) The Company shall indemnify and hold harmless each Holder, such
Holder's officers and employees and each person, if any, who controls such
Holder within the meaning of

                                       13
<PAGE>

the Securities Act (each, an "Indemnified Holder"), from and against any loss,
claim, damage or liability, joint or several, or any action in respect thereof
(including, but not limited to, any loss, claim, damage, liability or action
relating to resales of the Transfer Restricted Securities), to which such
Indemnified Holder may become subject, insofar as any such loss, claim, damage,
liability or action arises out of, or is based upon:

             (i)  any untrue statement or alleged untrue statement of a material
     fact contained in (A) the Shelf Registration Statement or Prospectus or any
     amendment or supplement thereto or (B) any blue sky application or other
     document or any amendment or supplement thereto prepared or executed by the
     Company (or based upon written information furnished by or on behalf of the
     Company expressly for use in such blue sky application or other document or
     amendment on supplement) filed in any jurisdiction specifically for the
     purpose of qualifying any or all of the Transfer Restricted Securities
     under the securities law of any state or other jurisdiction (such
     application or document being hereinafter called a "Blue Sky Application");
     or

             (ii) the omission or alleged omission to state therein any material
     fact required to be stated therein or necessary to make the statements
     therein, in the light of the circumstances under which they were made, not
     misleading,

and shall reimburse each Indemnified Holder promptly upon demand for any legal
or other expenses reasonably incurred by such Indemnified Holder in connection
with investigating or defending or preparing to defend against any such loss,
claim, damage, liability or action as such expenses are incurred; provided,
however, that the Company shall not be liable in any such case to the extent
that any such loss, claim, damage, liability or action arises out of, or is
based upon, any untrue statement or alleged untrue statement or omission or
alleged omission made in the Shelf Registration Statement or Prospectus or
amendment or supplement thereto or Blue Sky Application in reliance upon and in
conformity with written information furnished to the Company by or on behalf of
any Holder (or its related Indemnified Holder) specifically for use therein.
The foregoing indemnity agreement is in addition to any liability which the
Company may otherwise have to any Indemnified Holder.

     (b) Each Holder, severally and not jointly, shall indemnify and hold
harmless the Company, its officers and employees and each person, if any, who
controls the Company within the meaning of the Securities Act, from and against
any loss, claim, damage or liability, joint or several, or any action in respect
thereof, to which the Company or any such officer, employee or controlling
person may become subject, insofar as any such loss, claim, damage or liability
or action arises out of, or is based upon:

             (i)  any untrue statement or alleged untrue statement of any
     material fact contained in the Shelf Registration Statement or Prospectus
     or any amendment or supplement thereto or any Blue Sky Application; or

             (ii) the omission or the alleged omission to state therein any
     material fact required to be stated therein or necessary to make the
     statements therein, in light of the circumstances under which they were
     made, not misleading,

                                       14
<PAGE>

but in each case only to the extent that such untrue statement or alleged untrue
statement or omission or alleged omission was made in reliance upon and in
conformity with written information furnished to the Company by or on behalf of
such Holder (or its related Indemnified Holder) specifically for use therein,
and shall reimburse the Company and any such officer, employee or controlling
person promptly upon demand for any legal or other expenses reasonably incurred
by the Company or any such officer, employee or controlling person in connection
with investigating or defending or preparing to defend against any such loss,
claim, damage, liability or action as such expenses are incurred. The foregoing
indemnity agreement is in addition to any liability which any Holder may
otherwise have to the Company and any such officer, employee or controlling
person.

     (c) Promptly after receipt by an indemnified party under this Section 6 of
notice of any claim or the commencement of any action, the indemnified party
shall, if a claim in respect thereof is to be made against the indemnifying
party under this Section 6, notify the indemnifying party in writing of the
claim or the commencement of that action; provided, however, that the failure to
notify the indemnifying party shall not relieve it from any liability which it
may have under this Section 6 except to the extent it has been materially
prejudiced by such failure; and provided, further, that the failure to notify
the indemnifying party shall not relieve it from any liability which it may have
to an indemnified party otherwise than under this Section 6.  If any such claim
or action shall be brought against an indemnified party, and it shall notify the
indemnifying party thereof, the indemnifying party shall be entitled to
participate therein and, to the extent that it wishes, jointly with any other
similarly notified indemnifying party, to assume the defense thereof with
counsel satisfactory to the indemnified party.  After notice from the
indemnifying party to the indemnified party of its election to assume the
defense of such claim or action, the indemnifying party shall not be liable to
the indemnified party under this Section 6 for any legal or other expenses
subsequently incurred by the indemnified party in connection with the defense
thereof other than reasonable costs of investigation; provided, however, that a
Majority of Holders shall have the right to employ a single counsel to represent
jointly a Majority of Holders and their respective officers, employees and
controlling persons who may be subject to liability arising out of any claim in
respect of which indemnity may be sought by a Majority of Holders against the
Company under this Section 7;  and provided, further, that if a Majority of
Holders shall have reasonably concluded that there may be one or more legal
defenses available to them and their respective officers, employees and
controlling persons that are different from or additional to those available to
the Company and its officers, employees and controlling persons, the fees and
expenses of a single separate counsel shall be paid by the Company.  No
indemnifying party shall:

         (i)  without the prior written consent of the indemnified parties
     (which consent shall not be unreasonably withheld) settle or compromise or
     consent to the entry of any judgment with respect to any pending or
     threatened claim, action, suit or proceeding in respect of which
     indemnification or contribution may be sought hereunder (whether or not the
     indemnified parties are actual or potential parties to such claim or
     action) unless such settlement, compromise or consent includes an
     unconditional release of each indemnified party from all liability arising
     out of such claim, action, suit or proceeding, or

                                      15


<PAGE>

               (ii) be liable for any settlement of any such action effected
          without its written consent (which consent shall not be unreasonably
          withheld), but if settled with its written consent or if there be a
          final judgment for the plaintiff in any such action, the indemnifying
          party agrees to indemnify and hold harmless any indemnified party from
          and against any loss or liability by reason of such settlement or
          judgment.

          (d)  If the indemnification provided for in this Section 6 shall for
any reason be unavailable or insufficient to hold harmless an indemnified party
under Section 6(a) or 6(b) in respect of any loss, claim, damage or liability
(or action in respect thereof) referred to therein, each indemnifying party
shall, in lieu of indemnifying such indemnified party, contribute to the amount
paid or payable by such indemnified party as a result of such loss, claim,
damage or liability (or action in respect thereof):

               (i)  in such proportion as is appropriate to reflect the relative
          benefits received by the Company from the offering and sale of the
          Transfer Restricted Securities on the one hand and a Holder with
          respect to the sale by such Holder of the Transfer Restricted
          Securities on the other, or

               (ii) if the allocation provided by clause (6)(d)(i) is not
          permitted by applicable law, in such proportion as is appropriate to
          reflect not only the relative benefits referred to in clause 6(d)(i)
          but also the relative fault of the Company on the one hand and the
          Holder on the other in connection with the statements or omissions or
          alleged statements or alleged omissions that resulted in such loss,
          claim, damage or liability (or action in respect thereof), as well as
          any other relevant equitable considerations.

The relative benefits received by the Company on the one hand and a Holder on
the other with respect to such offering and such sale shall be deemed to be in
the same proportion as the total net proceeds from the offering of the
Debentures purchased under the Purchase Agreement (before deducting expenses)
received by the Company as set forth in the table on the cover of the Offering
Memorandum, dated January 27, 2000, on the one hand, bear to the total proceeds
received by such Holder with respect to its sale if Transfer Restricted
Securities on the other.  The relative fault of the parties shall be determined
by reference to whether the untrue or alleged untrue statement of a material
fact or the omission or alleged omission to state a material fact relates to
information supplied by the Company on the one hand or the Holders on the other,
the intent of the parties and their relative knowledge, access to information
and opportunity to correct or prevent such statement or omission.  The Company
and each Holder agree that it would not be just and equitable if the amount of
contribution pursuant to this Section 6(d) were determined by pro rata
allocation or by any other method of allocation that does not take into account
the equitable considerations referred to in the first sentence of this paragraph
(d).  The amount paid or payable by an indemnified party as a result of the
loss, claim, damage or liability, or action in respect thereof, referred to
above in this Section 6 shall be deemed to include, for purposes of this Section
6, any legal or other expenses reasonably incurred by such indemnified party in
connection with investigating or defending or preparing to defend any such
action or claim.  Notwithstanding the provisions of this Section 6, no Holder
shall be required to contribute any amount in excess of the amount by which the
total price at which the Transfer

                                       16
<PAGE>

Restricted Securities purchased by it were resold exceeds the amount of any
damages which such Holder has otherwise been required to pay by reason of any
untrue or alleged untrue statement or omission or alleged omission. No person
guilty of fraudulent misrepresentation (within the meaning of Section 11(f) of
the Securities Act) shall be entitled to contribution from any person who was
not guilty of such fraudulent misrepresentation. The Holders' obligations to
contribute as provided in this Section 6(d) are several and not joint.

          7.   Rule 144A.  In the event the Company is not subject to Section 13
or 15(d) of the Exchange Act, the Company hereby agrees with each Holder, for so
long as any Transfer Restricted Securities remain outstanding, to make available
to any Holder or beneficial owner of Transfer Restricted Securities in
connection with any sale thereof and any prospective purchaser of such Transfer
Restricted Securities from such Holder or beneficial owner, the information
required by Rule 144A(d)(4) under the Securities Act in order to permit resales
of such Transfer Restricted Securities pursuant to Rule 144A.

          8.   Participation in Underwritten Registrations.  No Holder may
participate in any Underwritten Registration hereunder unless such Holder:

                 (i)  agrees to sell such Holder's Transfer Restricted
          Securities on the basis provided in any underwriting arrangements
          approved by the Persons entitled hereunder to approve such
          arrangements; and

                 (ii) completes and executes all reasonable questionnaires,
          powers of attorney, indemnities, underwriting agreements, lock-up
          letters and other documents required under the terms of such
          underwriting arrangements.

          9.   Selection of Underwriters.  The Holders of Transfer Restricted
Securities covered by the Shelf Registration Statement who desire to do so may
sell such Transfer Restricted Securities in an Underwritten Offering.  In any
such Underwritten Offering, the investment banker or investment bankers and
manager or managers that will administer the offering will be selected by a
Majority of Holders whose Transfer Restricted Securities are included in such
offering; provided, however, that such investment bankers and managers must be
reasonably satisfactory to the Company.

          10.  Miscellaneous.

          (a)  Remedies.  The Company acknowledges and agrees that any failure
by the Company to comply with its obligations under Section 2 hereof may result
in material irreparable injury to the Initial Purchasers or the Holders for
which there is no adequate remedy at law, that it will not be possible to
measure damages for such injuries precisely and that, in the event of any such
failure, the Initial Purchasers or any Holder may obtain such relief as may be
required to specifically enforce the Company's obligations under Section 2
hereof. The Company further agrees to waive the defense in any action for
specific performance that a remedy at law would be adequate.

          (b)  Adjustments Affecting Transfer Restricted Securities.  The
Company shall not, directly or indirectly, take any action with respect to the
Transfer Restricted Securities as a class

                                       17
<PAGE>

that would adversely affect the ability of the Holders of Transfer Restricted
Securities to include such Transfer Restricted Securities in a registration
undertaken pursuant to this Agreement.

          (c)  No Inconsistent Agreements. The Company will not, on or after the
date of this Agreement, enter into any agreement with respect to its securities
that is inconsistent with the rights granted to the Holders in this Agreement or
otherwise conflicts with the provisions hereof. In addition, the Company shall
not grant to any of its security holders (other than the holders of Transfer
Restricted Securities in such capacity) the right to include any of its
securities in the Shelf Registration Statement provided for in this Agreement
other than the Transfer Restricted Securities. The Company has not previously
entered into any agreement (which has not expired or been terminated) granting
any registration rights with respect to its securities to any Person which
rights conflict with the provisions hereof.

          (d)  Amendments and Waivers. This Agreement may not be amended,
modified or supplemented, and waivers or consents to or departures from the
provisions hereof may not be given, unless the Company has obtained the written
consent of a Majority of Holders.

          (e)  Notices. All notices and other communications provided for or
permitted hereunder shall be made in writing by hand-delivery, first-class mail
(registered or certified, return receipt requested), telex, telecopier, or air
courier guaranteeing overnight delivery:

                 (i)  if to a Holder, at the address set forth on the records of
          the registrar under the Indenture or the transfer agent of the Common
          Stock, as the case may be; and

                 (ii) if to the Company:

                      CuraGen Corporation

                      555 Long Wharf Drive, 11/th/ Floor
                      New Haven, Connecticut 06511
                      Attention: Elizabeth Whayland, Corporate Secretary

                      With a copy to:

                      Mintz, Levin, Cohn, Ferris, Glovsky and Popeo, P.C.
                      One Financial Center
                      Boston, Massachusetts 02111
                      Attention: Michael Fantozzi

          All such notices and communications shall be deemed to have been duly
given at: the time delivered by hand, if personally delivered; five Business
Days after being deposited in the mail, postage prepaid, if mailed; when
answered back, if telexed; when receipt acknowledged, if telecopied; and on the
next Business Day, if timely delivered to an air courier guaranteeing overnight
delivery.

          (f)  Successors and Assigns.  This Agreement shall inure to the
benefit of and be binding upon the successors and assigns of each of the
parties, including without limitation and without the need for an express
assignment, subsequent Holders of Transfer Restricted

                                       18
<PAGE>

Securities; provided, however, that (i) this Agreement shall not inure to the
benefit of or be binding upon a successor or assign of a Holder unless and to
the extent such successor or assign acquired Transfer Restricted Securities from
such Holder and (ii) nothing contained herein shall be deemed to permit any
assignment, transfer or other disposition of Transfer Restricted Securities in
violation of the terms of the Purchase Agreement or the Indenture. If any
transferee of any Holder shall acquire Transfer Restricted Securities, in any
manner, whether by operation of law or otherwise, such Transfer Restricted
Securities shall be held subject to all of the terms of this Agreement, and by
taking and holding such Transfer Restricted Securities such person shall be
conclusively deemed to have agreed to be bound by and to perform all of the
terms and provisions of this Agreement.

          (g) Counterparts. This Agreement may be executed in any number of
counterparts and by the parties hereto in separate counterparts, each of which
when so executed shall be deemed to be an original and all of which taken
together shall constitute one and the same agreement.

          (h) Securities Held by the Company or Their Affiliates.  Whenever the
consent or approval of Holders of a specified percentage of Transfer Restricted
Securities is required hereunder, Transfer Restricted Securities held by the
Company or its Affiliates shall not be counted in determining whether such
consent or approval was given by the Holders of such required percentage.

          (i) Headings. The headings in this Agreement are for convenience of
reference only and shall not limit or otherwise affect the meaning hereof.

          (j) Governing Law.  This Agreement shall be governed by, and construed
in accordance with, the law of the State of New York.

          (k) Severability. If any one or more of the provisions contained
herein, or the application thereof in any circumstance, is held invalid, illegal
or unenforceable, the validity, legality and enforceability of any such
provision in every other respect and of the remaining provisions contained
herein shall not be affected or impaired thereby.

          (l) Entire Agreement.  This Agreement is intended by the parties as a
final expression of their agreement and intended to be a complete and exclusive
statement of the agreement and understanding of the parties hereto in respect of
the subject matter contained herein. There are no restrictions, promises,
warranties or undertakings, other than those set forth or referred to herein
with respect to the registration rights granted by the Company with respect to
the Transfer Restricted Securities. This Agreement supersedes all prior
agreements and understandings between the parties with respect to such subject
matter.

                                       19
<PAGE>

          In Witness Whereof, the parties have executed this Agreement as of the
date first written above.



                                        CuraGen Corporation

                                        By /s/ David M. Wurzer
                                           -------------------------------------
                                           Name: David M. Wurzer
                                           Title: EVP & CFO

                                        Lehman Brothers Inc.
                                        Morgan Stanley & Co. Incorporated
                                        Dain Rauscher Incorporated


                                        By: Lehman Brothers Inc.


                                        By /s/ Arlene Salmonson
                                           -------------------------------------
                                           Authorized Representative
<PAGE>

                                                                       Exhibit A

                              CURAGEN CORPORATION

                       NOTICE OF REGISTRATION STATEMENT

                                      AND

               SELLING SECURITYHOLDER ELECTION AND QUESTIONNAIRE

________________________________________________________________________________

                                    NOTICE

     CuraGen Corporation (the "Company") has filed, or intends to file, with the
Securities and Exchange Commission (the "Commission") a registration statement
on Form S-3 or such other Form as may be available (the "Shelf Registration
Statement"), for the registration and resale under Rule 415 of the Securities
Act of 1933, as amended (the "Securities Act"), of the Company's 6.00%
Convertible Subordinated Debentures due 2007 (CUSIP No. ) (the "Debentures"),
and common stock, par value $0.01 per share, issuable upon conversion thereof
(the "Shares" and together with the Debentures, the "Transfer Restricted
Securities") in accordance with the terms of the Registration Rights Agreement,
dated as of February 2, 2000 (the "Registration Rights Agreement") between the
Company and Lehman Brothers Inc., Morgan Stanley & Co. Incorporated and Dain
Rauscher Incorporated. A copy of the Registration Rights Agreement is available
from the Company upon request at the address set forth below. All capitalized
terms not otherwise defined herein have the meaning ascribed thereto in the
Registration Rights Agreement.

     In order to sell or otherwise dispose of any Transfer Restricted Securities
pursuant to the Shelf Registration Statement, a beneficial owner of Transfer
Restricted Securities generally will be required to be named as a selling
securityholder in the related Prospectus, deliver a Prospectus to purchasers of
Transfer Restricted Securities, be subject to certain civil liability provisions
of the Securities Act and be bound by those provisions of the Registration
Rights Agreement applicable to such beneficial owner (including certain
indemnification rights and obligations, as described below). In order to be
included in the Shelf Registration Statement, this Election and Questionnaire
must be completed, executed and delivered to the Company at the address set
forth herein for receipt PRIOR TO OR ON [insert here date that is 20 business
days from the date of this notice] (the "Election and Questionnaire Deadline").
Beneficial owners that do not complete this Notice and Questionnaire prior to
the Election and Questionnaire Deadline and deliver it to the Company as
provided below will not be named as selling securityholders in the prospectus
and therefore will not be permitted to sell any Transfer Restricted Securities
pursuant to the Shelf Registration Statement.

     Certain legal consequences arise from being named as a selling
securityholder in the Shelf Registration Statement and the related Prospectus.
Accordingly, holders and beneficial owners of Transfer Restricted Securities are
advised to consult their own securities law counsel

                                      A-1
<PAGE>

regarding the consequences of being named or not being named as a selling
securityholder in the Shelf Registration Statement and the related Prospectus.


                                   ELECTION

     The undersigned Holder (the "Selling Securityholder") of Transfer
Restricted Securities hereby elects to include in the Shelf Registration
Statement the Transfer Restricted Securities beneficially owned by it and listed
below in Item 3 (unless otherwise specified under Item 3) pursuant to the Shelf
Registration Statement. The undersigned, by signing and returning this Election
and Questionnaire, understands that it will be bound by the terms and conditions
of this Election and Questionnaire and the Registration Rights Agreement.

     Pursuant to the Registration Rights Agreement, the Selling Securityholder
has agreed to indemnify and hold harmless the Company, the Company's directors,
the Company's officers who sign the Shelf Registration Statement and each
person, if any, who controls the Company within the meaning of either Section 15
of the Securities Act or Section 20 of the Exchange Act, from and against
certain losses arising in connection with statements concerning the Selling
Securityholder made in the Shelf Registration Statement or the related
Prospectus in reliance upon the information provided in this Election and
Questionnaire.

     The Selling Securityholder hereby provides the following information to the
Company and represents and warrants that such information is accurate and
complete:

                                 QUESTIONNAIRE

1.   (a)  Full legal name of Selling Securityholder:

     (b)  Full legal name of registered holder (if not the same as (a) above)
          through which Transfer Restricted Securities listed in (3) below are
          held:

     (c)  Full legal name of DTC participant (if applicable and if not the same
          as (b) above) through which Transfer Restricted Securities listed in
          (3) are held:

2.   Address for notices to Selling Securityholders:

     Telephone:

     Fax:

     Contact Person:

3.   Beneficial ownership of Transfer Restricted Securities:

     (a)  Type of Transfer Restricted Securities beneficially owned, and
          principal amount of Debentures or number of shares of Common Stock, as
          the case may be, beneficially owned:

                                      A-2
<PAGE>

     (b)  CUSIP No(s). of such Transfer Restricted Securities beneficially
          owned:

4.   Beneficial ownership of the Company's securities owned by the Selling
Securityholder:

     Except as set forth below in this Item (4), the undersigned is not the
     beneficial or registered owner of any securities of the Company other than
     the Transfer Restricted Securities listed above in Item (3) ("Other
     Securities").

     (a)  Type and amount of Other Securities beneficially owned by the Selling
          Securityholder:

     (b)  CUSIP No(s). of such Other Securities beneficially owned:

5.   Relationship with the Company

     Except as set forth below, neither the undersigned nor any of its
     affiliates, officers, directors or principal equity holders (5% or more)
     has held any position or office or has had any other material relationship
     with the Company (or their predecessors or affiliates) during the past
     three years.

     State any exceptions here:

6.   Plan of Distribution

     Except as set forth below, the undersigned (including its donees or
     pledgees) intends to distribute the Transfer Restricted Securities listed
     above in Item (3) pursuant to the Shelf Registration Statement only as
     follows (if at all).  Such Transfer Restricted Securities may be sold from
     time to time directly by the undersigned or, alternatively, through
     underwriters, broker-dealers or agents.  If the Transfer Restricted
     Securities are sold through underwriters or broker-dealers, the Selling
     Securityholder will be responsible for underwriting discounts or
     commissions or agent's commissions.  Such Transfer Restricted Securities
     may be sold in one or more transactions at fixed prices, at prevailing
     market prices at the time of sale, at varying prices determined at the time
     of sale, or at negotiated prices.  Such sales may be effected in
     transactions (which may involve crosses or block transactions):

          (i)    on any national securities exchange or quotation service on
     which the Transfer Restricted Securities may be listed or quoted at the
     time of sale;

          (ii)   in the over-the-counter market;

                                      A-3
<PAGE>

          (iii)  in transactions otherwise than on such exchanges or services or
     in the over-the-counter market; or

          (iv)   through the writing of options.

     In connection with sales of the Transfer Restricted Securities or
     otherwise, the undersigned may enter into hedging transactions with broker-
     dealers, which may in turn engage in short sales of the Transfer Restricted
     Securities and deliver Transfer Restricted Securities to close out such
     short positions, or loan or pledge Transfer Restricted Securities to
     broker-dealers that in turn may sell such securities.

     State any exceptions here:

     Note: In no event will such method(s) of distribution take the form of an
underwritten offering of the Transfer Restricted Securities without the prior
agreement of the Company.

     By signing below, the Selling Securityholder acknowledges that it
understands its obligation to comply, and agrees it will comply, with the
provisions of the prospectus delivery and other provisions of the Securities Act
and the Exchange Act and the respective rules and regulations promulgated
thereunder, particularly Regulation M thereunder (or any successor rules or
regulations), in connection with any offering of Transfer Restricted Securities
pursuant to the Shelf Registration Statement.

     If the Selling Securityholder transfers all or any portion of the Transfer
Restricted Securities listed in Item 3 above after the date on which such
information is provided to the Company, the Selling Securityholder agrees to
notify the transferee(s) at the time of the transfer of its rights and
obligations under this Election and Questionnaire and the Registration Rights
Agreement.

     By signing below, the undersigned consents to the disclosure of the
information contained herein in its answers to items (1) through (6) above and
the inclusion of such information in the Shelf Registration Statement and the
related Prospectus. The undersigned understands that such information will be
relied upon by the Company in connection with the preparation or amendment of
the Shelf Registration Statement and the related Prospectus.

     In accordance with the Selling Securityholder's obligation under the
Registration Rights Agreement to provide such information as may be required by
law for inclusion in the Shelf Registration Statement, the Selling
Securityholder agrees to promptly notify the Company of any inaccuracies or
changes in the information provided herein that may occur subsequent to the date
hereof at any time while the Shelf Registration Statement remains effective. All
notices hereunder and pursuant to the Registration Rights Agreement shall be
made in writing at the address set forth below.

     Once this Election and Questionnaire is executed by the Selling
Securityholder and received by the Company, the terms of this Election and
Questionnaire and the representations and warranties contained herein shall be
binding on, shall inure to the benefit of and shall be enforceable by the
respective successors, heirs, personal representatives and assigns of the

                                      A-4
<PAGE>

Company and the Selling Securityholder with respect to the Transfer Restricted
Securities beneficially owned by such Selling Securityholder and listed in Item
3 above.  This Agreement shall be governed by, and construed in accordance with,
the laws of the State of New York.

                                      A-5
<PAGE>

     IN WITNESS WHEREOF, the undersigned, by authority duly given, has caused
this Election and Questionnaire to be executed and delivered either in person or
by its duly authorized agent.

Dated:


Beneficial Owner


By: _________________________
    Name:
    Title:


Please return the completed and executed Election and Questionnaire for receipt
prior to or on [insert date of Election and Questionnaire Deadline] to CuraGen
Corporation at:

          CuraGen Corporation
          555 Long Wharf Drive, 11/th/ Floor
          New Haven, Connecticut 06511
          Attention: Elizabeth A. Whayland, Secretary

                                      A-6
<PAGE>

                                                            EXHIBIT 1 TO ANNEX A

                          NOTICE OF TRANSFER PURSUANT
                           TO REGISTRATION STATEMENT



CuraGen Corporation
555 Long Wharf Drive, 11/th/ Floor
New Haven, Connecticut 06511

The Chase Manhattan Bank
450 West 33/rd/ Street, 10/th/ Floor
New York, New York 10001
Attn:  Capital Markets Fiduciary Services

            Re:  CuraGen Corporation's 6.00% Convertible Subordinated Debentures
                 due 2007 (the "Debentures")

Dear Sirs:

          Please be advised that          has transferred $           aggregate
principal amount of the above-referenced Debentures or          shares of the
Company's Common Stock issued on conversion or repurchase of Debentures,
pursuant to the Registration Statement on Form S-3 (File No. 333-     ) filed by
the Company.

          We hereby certify that the prospectus delivery requirements, if any,
of the Securities Act of 1933, as amended, have been satisfied with respect to
the transfer described above and that the above named beneficial owner of the
Debentures or Common Stock is named as a selling securityholder in the
Prospectus dated          , or in amendments or supplements thereto, and that
the aggregate principal amount of the Debentures or number of shares of Common
Stock transferred are [all or a portion of] the Debentures or Common Stock
listed in such Prospectus, as amended or supplemented, opposite such owner's
name.

                                    Very truly yours,


                                    [name]
                                    By: __________________________________
                                             (Authorized signature)


Dated: ___________________________

                                      A-7