FORM 8-A

                       SECURITIES AND EXCHANGE COMMISSION
                              WASHINGTON, DC 20549

                FOR REGISTRATION OF CERTAIN CLASSES OF SECURITIES
                     PURSUANT TO SECTION 12(b) OR (g) OF THE
                         SECURITIES EXCHANGE ACT OF 1934

                                   ENZON, INC.
               (Exact name of Registrant as Specified in Charter)

               Delaware                                     22-2372868
(State of Incorporation or Organization)       (IRS Employer Identification No.)

20 Kingsbridge Road, Piscataway, New Jersey 08854               10014
    (Address of Principal Executive Offices)                 (Zip Code)

If this form relates to the               If this form relates to the
registration of a class of securities     registration of a class of securities
pursuant to Section 12(b) of the          pursuant to Section 12(g) of the
Exchange Act and is effective             Exchange Act and is effective pursuant
pursuant to General Instruction           to General Instruction A.(d), please
A.(c), please check the following         check the following
box. |_|                                  box. |X|

         Securities Act registration statement file number to which this
                                  form relates:

                                 _______________
                                 (If applicable)

       Securities to be registered pursuant to Section 12(b) of the Act:

     -----------------------               ----------------------------------
       Title of Each Class                   Name of Each Exchange on Which
       to be so Registered                   Each Class is to be Registered
       -------------------                 ----------------------------------

       ___________________                        ___________________

       ___________________                        ___________________

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

       Securities to be registered pursuant to Section 12(g) of the Act:

                    Series B Preferred Stock Purchase Rights
                                (Title of Class)

                    ________________________________________
                                (Title of Class)



Item 1. Description of Registrant's Securities to be Registered.

      On May 17, 2002 the Board of Directors of Enzon, Inc. (the "Company"),
declared a dividend of one preferred share purchase right (a "Right") per share
for each outstanding share of Common Stock, par value $0.01 (the "Common
Shares"), of the Company. The dividend will be payable on June 3, 2002 (the
"Record Date") to holders of record of the Common Shares on that date.

      Each Right entitles the registered holder to purchase from the Company one
one-thousandth of a share of Series B Preferred Stock, par value $0.01 (the
"Preferred Shares"), of the Company at a price of $190.00 per one one-thousandth
of a Preferred Share (the "Purchase Price"), subject to adjustment; provided,
however, under the circumstances described below, holders may receive Common
Shares instead of Preferred Shares. The description and terms of the Rights are
set forth in the Rights Agreement, dated as of May 17, 2002 (the "Rights
Agreement"), between the Company and Continental Stock Transfer & Trust Company,
as Rights Agent (the "Rights Agent"). Capitalized terms used herein but not
defined shall have the meaning assigned to them in the Rights Agreement.

      The following summary of the principal terms of the Rights Agreement is a
general description only and is subject to the detailed terms and conditions of
the Rights Agreement. A copy of the Rights Agreement is filed as Exhibit 1 to
this Form 8-A and is incorporated herein by reference.

      Initially, the Rights will attach to all certificates representing Common
Shares then outstanding and no separate Right Certificates (as defined herein)
will be distributed. The Rights will separate from the Common Shares, and a
Distribution Date for the Rights will occur upon the earlier of:

            (i) the close of business on the day following a public announcement
      that a person or group of affiliated or associated persons has become an
      "Acquiring Person" (i.e., has become, subject to certain exceptions, the
      Beneficial Owner of 15% (the "Threshold Percentage") or more of the
      outstanding Common Shares); and

            (ii) the close of business on the day following the commencement or
      public announcement of the intention to commence a tender offer or
      exchange offer, the consummation of which would result in a person or
      group of affiliated or associated persons becoming, subject to certain
      exceptions, the Beneficial Owner of the Threshold Percentage or more of
      the outstanding Common Shares (or such later date as may be determined by
      the Board of Directors of the Company prior to a person or group of
      affiliated or associated persons becoming an Acquiring Person).

      A Person will not be an Acquiring Person if the Board of Directors of the
Company determines that such Person became the Beneficial Owner of the Threshold
Percentage or more of the Common Shares of the Company then outstanding
inadvertently and such Person divests itself, within a reasonable period of time
as determined by the Board of Directors, of a sufficient number of Common Shares
so that such Person is no longer the Beneficial Owner of the Threshold
Percentage or more of the Common Shares of the Company then outstanding.

      Until the Distribution Date,

            (i) the Rights will be evidenced by the Common Share certificates
      and will be transferred with and only with the Common Shares,

            (ii) new Common Share certificates issued after the Record Date upon
      transfer or new issuance of the Common Shares will contain a notation
      incorporating the Rights Agreement by reference, and

            (iii) the surrender for transfer of any Common Share certificate,
      even without such notation or a copy of the Summary of Rights distributed
      to stockholders of record as of the Record Date, also will constitute the
      transfer of the Rights associated with the Common Shares represented by
      such certificate.

      As promptly as practicable following the Distribution Date, separate
certificates evidencing the Rights ("Right Certificates") will be mailed to
holders of record of the Common Shares as of the close of business on the
Distribution Date, and such separate Right Certificates alone will evidence the
Rights.


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      The Rights are not exercisable until the Distribution Date. The Rights
will expire on May 16, 2012, unless extended or earlier redeemed or exchanged by
the Company as described below.

      The Purchase Price payable, and the number of Preferred Shares or other
securities or property issuable upon exercise of the Rights, are subject to
adjustment from time to time to prevent dilution:

            (i) in the event of a stock dividend on, or a subdivision,
      combination or reclassification of, the Preferred Shares,

            (ii) upon the grant to holders of the Preferred Shares of certain
      rights, options or warrants to subscribe for or purchase Preferred Shares
      or securities convertible into Preferred Shares or preferred share
      equivalents at less than the then current market price of the Preferred
      Shares, or

            (iii) upon the distribution to holders of the Preferred Shares of
      evidences of indebtedness or assets (excluding regular periodic cash
      dividends or dividends payable in Preferred Shares) or of subscription
      rights or warrants (other than those described in clause (ii) of this
      paragraph).

      With certain exceptions, no adjustment in the Purchase Price will be
required until cumulative adjustments require an adjustment of at least 1% in
the Purchase Price. No fraction of a Preferred Share will be issued (other than
fractional shares which are integral multiples of one one-thousandth of a
Preferred Share, which may, at the election of the Company, be evidenced by
depositary receipts) if in lieu thereof, a payment in cash is made based on the
closing price (prorated for the fraction) of a Preferred Share on the last
trading date prior to the date of exercise.

      The number of outstanding Rights and the number of one one-thousandths of
a Preferred Share issuable upon exercise of each Right also are subject to
adjustment in the event of a stock split of the Common Shares, a stock dividend
on the Common Shares payable in Common Shares, or subdivisions, consolidations
or combinations of the Common Shares occurring, in any such case, prior to the
Distribution Date.

      Preferred Shares purchasable upon exercise of the Rights will not be
redeemable. Each Preferred Share will be entitled to a minimum preferential
quarterly dividend payment of the greater of (a) $1.00 or (b) subject to the
provision for adjustment, 1,000 times the aggregate per share amount of all cash
dividends, and 1,000 times the aggregate per share amount (payable in kind) of
all non-cash dividends or other distributions declared on the Common Shares
since the immediately preceding Quarterly Dividend Payment Date or, with respect
to the first Quarterly Dividend Payment Date, since the first issuance of any
share or fraction of a share of the Preferred Shares. In the event of
liquidation, the holders of the Preferred Shares would be entitled to receive a
preferential liquidation payment of the greater of (i) $1,000 per share, plus an
amount equal to accrued and unpaid dividends and distributions thereon, whether
or not declared, to the date of such payment, or (ii) an aggregate amount per
share, subject to the provision for adjustment hereinafter set forth, equal to
1,000 times the aggregate amount to be distributed per share to holders of
Common Shares, or to the holders of shares of stock ranking on a parity (either
as to dividends or upon liquidation, dissolution or winding up) with the
Preferred Shares. Each Preferred Share will have 1,000 votes, voting together
with the Common Shares. Finally, in the event of any merger, consolidation or
other transaction in which Common Shares are exchanged, each Preferred Share
will be entitled to receive 1,000 times the amount received per Common Share.
These rights are protected by customary antidilution provisions.

      Because of the nature of the Preferred Shares' dividend, liquidation and
voting rights, the value of the one one-thousandth interest in a Preferred Share
purchasable upon exercise of each Right should approximate the value of one
Common Share.

      If any person or group of affiliated or associated persons becomes an
Acquiring Person (unless the event by which such Person became an Acquiring
Person is a Permitted Offer described in the following paragraph), then each
holder of a Right, other than Rights beneficially owned by the Acquiring Person
and certain transferees thereof (which will thereafter be void), will thereafter
have the right to receive, upon exercise thereof at the then current Purchase
Price of the Right, that number of Common Shares having a market value of two
times such Purchase Price of the Right, subject to certain possible adjustments.

      If, at any time after there is an Acquiring Person, the Company is
acquired in certain mergers or other business combination transactions (other
than certain transactions with a subsidiary of the Company or a transaction with
a person who acquired Common Shares through a tender offer or exchange offer for
all outstanding Common Shares of the Company determined by the Board of
Directors to be in the best interests of the Company and its


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stockholders (a "Permitted Offer") or 50% or more of the assets or earning power
of the Company and its subsidiaries (taken as a whole) are sold, each holder of
a Right (other than Rights which have become void under the terms of the Rights
Agreement) will thereafter have the right to receive, upon exercise thereof at
the then current Purchase Price of the Right, that number of Common Shares of
the acquiring company (or, in certain cases, one of its affiliates) having a
market value of two times such Purchase Price of the Right.

      In certain events specified in the Rights Agreement, the Company is
permitted temporarily to suspend the exercisability of the Rights.

      At any time after a person or group of affiliated or associated persons
becomes an Acquiring Person, and prior to the acquisition by a person or group
of affiliated or associated persons of 50% or more of the outstanding Common
Shares, the Board of Directors of the Company may exchange all or part of the
Rights (other than Rights which have become void under the terms of the Rights
Agreement) for Common Shares at an exchange ratio of one Common Share per Right,
subject to adjustment.

      At any time prior to such time as any Person becomes an Acquiring Person,
the Board of Directors of the Company may redeem the Rights in whole, but not in
part, at a price of $.01 per Right, subject to adjustment, payable in cash,
Common Shares or any other form of consideration deemed appropriate by the Board
of Directors. The period of time during which the Rights may be redeemed may be
extended if no person has become an Acquiring Person. The redemption of the
Rights may be made effective at such time, on such basis and with such
conditions as the Board of Directors in its sole discretion may establish.

      Until a Right is exercised, the holder thereof, as such, will have no
rights as a stockholder of the Company, including without limitation, the right
to vote or to receive dividends. In addition, the Company will have no liability
to holders of Rights or of the Common Shares for any failure to comply with the
Rights Agreement during any period the Board of Directors is unaware of the
existence of the Acquiring Person.

      Takeover attempts frequently include coercive tactics to deprive the
Company's Board of Directors and its stockholders of any real opportunity to
determine the destiny of the Company. The Rights have been declared by the Board
in order to deter such tactics which do not maximize stockholder value,
including a gradual accumulation of shares in the open market of 15% or greater
position to be followed by a merger or a partial or two-tier tender offer that
does not treat all stockholders equally. These tactics unfairly pressure
stockholders, squeeze them out of their investment without giving them any real
choice and deprive them of the full value of their shares.

      The Rights approved by the Board of Directors are designed to protect and
maximize the value of the outstanding equity interests in the Company in the
event of an unsolicited attempt by an acquirer to take over the Company in a
manner or on terms not approved by the Board of Directors. Subject to the
restrictions described above, the Rights may be redeemed by the Company at $0.01
per Right at any time prior to such time as any Person becomes an Acquiring
Person. Accordingly, the Rights should not interfere with any merger or business
combination approved by the Board of Directors.

      However, the Rights may have the effect of rendering more difficult or
discouraging an acquisition of the Company deemed undesirable by the Board of
Directors. The Rights may cause substantial dilution to a person or group that
attempts to acquire the Company on terms or in a manner not approved by the
Company's Board of Directors, except pursuant to an offer conditioned upon the
negation, purchase or redemption of the Rights.

      Issuance of the Rights does not in any way weaken the financial strength
of the Company or interfere with its business plans. The issuance of the Rights
themselves has no dilutive effect, will not affect reported earnings per share,
should not be taxable to the Company or to its stockholders, and will not change
the way in which the Company's Common Shares are presently traded.


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      Item 2. Exhibits

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      1     Rights Agreement dated as of May 17, 2002 ("Rights Agreement")
            between the Company 1 and Continental Stock Transfer & Trust
            Company, as Rights Agent.

      2     Form of Certificate of Designation with respect to the Series B
            Preferred Stock, par value $.01 per share, of the Company (filed as
            Exhibit A to the Rights Agreement).

      3     Form of Right Certificate (filed as Exhibit B to the Right
            Agreement). Pursuant to the Rights Agreement, printed Right
            Certificates will not be mailed until the Distribution Date (as
            defined in the Rights Agreement).

      4     Summary of Rights (filed as Exhibit C to the Rights Agreement).
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                                    SIGNATURE

      Pursuant to the requirements of Section 12 of the Securities Exchange Act
of 1934, the registrant has duly caused this registration statement to be signed
on its behalf by the undersigned, thereto duly authorized.

                                        ENZON, INC.


                                        By: /s/ Arthur J. Higgins
                                          --------------------------------------
                                        Name: Arthur J. Higgins
                                        Title: President and Chief Executive
                                               Officer

Dated: May 22, 2002


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