SECURITIES AND EXCHANGE COMMISSION

                            WASHINGTON, D. C. 20549

                                 ____________


                                   FORM 8-A

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


                              INSMED INCORPORATED
            (Exact name of registrant as specified in its charter)


                Virginia                                   54-1972729
                --------                                   ----------
(State of incorporation or organization)                  (IRS employer
                                                       identification no.)

       800 East Leigh Street
         Richmond, Virginia                                    23219
         ------------------                                    -----
(Address of principal executive offices)                    (Zip code)


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



 Securities Act registration statement file number to which this form relates:
                                     None


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

           N/A                                          N/A
           ---                                          ---


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

                        Preferred Stock Purchase Rights
                        -------------------------------
                               (Title of class)


ITEM 1.    Description of Registrant's Securities to be Registered.
           -------------------------------------------------------

     On May 16, 2001 (the "Rights Authorization Date"), the Board of Directors
of Insmed Incorporated, a corporation organized under the laws of the
Commonwealth of Virginia (the "Company"), approved a Rights Agreement, dated as
of and to be effective as of May 16, 2001 (the "Rights Agreement"), between the
Company and First Union National Bank, as Rights Agent, having the principal
terms summarized below.  In accordance with the Rights Agreement, the Board also
declared a dividend distribution of one right ("Right") for each outstanding
share of common stock of the Company (the "Common Stock") to shareholders of
record at the close of business on June 1, 2001 (the "Record Date").

     Each Right entitles the holder to purchase from the Company one one-
thousandth (1/1000/th/) of a share of a series of the Company's preferred stock
designated as Series A Junior Participating Preferred Stock ("Preferred Stock")
at a price of $35 per one one-thousandth (1/1000/th/) of a share, subject to
adjustment (the "Purchase Price").  Each one one-thousandth of a share of
Preferred Stock is structured to be the equivalent of one share of Common Stock
of the Company ("Common Stock").  Shareholders will receive one Right per share
of Common Stock held of record at the close of business on the Record Date.

     Initially, the Rights will be attached to all Common Stock certificates
representing shares then outstanding, and no separate Rights Certificates will
be distributed.  Subject to certain exceptions specified in the Rights
Agreement, the Rights will separate from the Common Stock and a distribution of
the Rights Certificates will occur ("Distribution Date") upon the earlier of (i)
the Close of Business on the tenth Business Day following a public announcement
that a person or group of affiliated or associated persons (an "Acquiring
Person") has acquired, or obtained the right to acquire,  beneficial ownership
of 15% or more of the outstanding shares of Common Stock (the "Stock Acquisition
Date"), other than as a result of repurchases of stock by the Company or through
inadvertance by certain institutional shareholders or (ii) the Close of Business
on the tenth Business Day (or such later date as the Board shall determine)
following the commencement of a tender offer or exchange offer that would result
in a person or group becoming an Acquiring Person.  Until the Distribution Date,
(i) the Rights will be evidenced by the Common Stock certificates and will be
transferred with and only with such Common Stock certificates, (ii) new Common
Stock certificates issued after the Record Date will contain a legend
incorporating the Rights Agreement by reference and (iii) the surrender for
transfer of any certificates for Common Stock outstanding will also constitute
the transfer of the Rights associated with the Common Stock represented by such
certificate.  Pursuant to the Rights Agreement, the Company reserves the right
to require prior to the occurrence of a Triggering Event (as defined below)
that, upon any exercise of Rights, a number of Rights be exercised so that only
whole shares of Preferred Stock will be issued.

     The Rights are not exercisable until the Distribution Date and will expire
at 5:00 P.M. (Richmond, Virginia time) on May 16, 2011 (the "Expiration Date"),
unless such date is extended or the Rights are earlier redeemed or exchanged by
the Company as described below.

     As soon as practicable after the Distribution Date, Rights Certificates
will be mailed to holders of record of the Common Stock as of the close of
business on the Distribution Date and, thereafter, the separate Right
Certificates alone will represent the Rights.  Except as otherwise


determined by the Board of Directors of the Company or as provided in the Rights
Agreement, only shares of Common Stock issued prior to the Distribution Date
will be issued with Rights.

     In the event that a Person becomes an Acquiring Person, each holder of a
Right will thereafter have the right to receive, upon exercise, Common Stock
(or, in certain circumstances, cash, property or other securities of the
Company) having a value equal to two times the purchase price of the Right.
Notwithstanding any of the foregoing, following the occurrence of the event set
forth in this paragraph, all Rights that are, or (under certain circumstances
specified in the Rights Agreement) were, beneficially owned by any Acquiring
Person will be null and void.  However, Rights are not exercisable following the
occurrence of the event set forth above until such time as the Rights are no
longer redeemable by the Company as set forth below.

     For example, at an exercise price of $35 per Right, each Right not owned by
an Acquiring Person (or by certain related parties) following an event set forth
in the preceding paragraph would entitle its holder to purchase $70 worth of
Common Stock (or other consideration, as noted above) for $35.  Assuming that
the Common Stock had a per share value of $10 at such time, the holder of each
valid Right would be entitled to purchase seven shares of Common Stock for an
aggregate of $35.

     In the event that, on or at any time after a Stock Acquisition Date, the
Company (i) engages in a merger, statutory share exchange, or other business
combination transaction (in which the Company is not the surviving corporation),
(ii) the Company engages in a merger, statutory share exchange, or other
business combination transaction in which the Company is the surviving
corporation and any shares of the Company's Common Stock are changed into or
exchanged for other securities or assets or (iii) 50% or more of the assets,
cash flow or earning power of the Company and its subsidiaries (taken as a
whole) are sold or transferred, each holder of a Right (except as noted below)
shall thereafter have the right to receive, upon the exercise thereof at the
then current purchase price of the Right, that number of shares of common stock
of the acquiring company which at the time of such transaction would have a
market value (determined as provided in the Rights Agreement) of two times the
purchase price of the Right.  The events set forth in this paragraph and in the
second preceding paragraph are referred to as the "Triggering Events."

     Upon the occurrence of a Triggering Event that entitles Rights holders to
purchase securities or assets of the Company, Rights that are or were owned by
the Acquiring Person, or any affiliate or associate of such Acquiring Person, on
or after such Acquiring Person's Stock Acquisition Date shall be null and void
and shall not thereafter be exercised by any person (including subsequent
transferees).  Upon the occurrence of a Triggering Event that entitles Rights
holders to purchase common stock of a third party, or upon the authorization of
an Exchange (as defined below), Rights that are or were owned by any Acquiring
Person or any affiliate or associate of any Acquiring Person on or after such
Acquiring Person's Stock Acquisition Date shall be null and void and shall not
thereafter be exercised by any person (including subsequent transferees).

                                      -2-


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

     At any time (including a time after any person becomes an Acquiring
Person), the Company may exchange all or part of the Rights (except as set forth
below) for shares of Common Stock (an "Exchange") at an exchange ratio of one
share per Right, as appropriately adjusted to reflect any stock split or similar
transaction.

     At any time prior to the earlier of (i) ten days following the Stock
Acquisition Date, and (ii) the Expiration Date, or said later date as the Board
may set, the Company may redeem the Rights in whole, but not in part, at a price
of $.01 per Right (the "Redemption Price"). Immediately upon the action of the
Board ordering redemption of the Rights, the Rights will terminate and the only
right of the holders of Rights will be to receive the Redemption Price.

     Until a Right is exercised, the holder thereof, as such, will have no
rights as a shareholder of the Company, including, without limitation, the right
to vote or to receive dividends.  While the distribution of the Rights will not
be taxable to shareholders or to the Company, shareholders may, depending upon
the circumstances, recognize taxable income in the event that the Rights become
exercisable for Common Stock (or other consideration) of the Company or for
common stock of the acquiring company or in the event of the redemption of the
Rights, as set forth above.

     Other than certain provisions relating to the principal economic terms of
the Rights, any of the provisions of the Rights Agreement may be amended by the
Board prior to the Distribution Date.  After the Distribution Date, the
provisions of the Rights Agreement may be amended by the Board in order to cure
any ambiguity, to make certain other changes that do not adversely affect the
interests of holders of Rights (excluding the interests of any Acquiring
Person), or to shorten or lengthen any time period under the Rights Agreement;
provided, however, no amendment to adjust the time period governing redemption
may be made at such time as the Rights are not redeemable.

     The Rights Agreement (which includes as (i) Exhibit A the form of Articles
of Amendment to the Company's Articles of Incorporation, as amended, (ii)
Exhibit B the form of Rights Certificate, and (iii) Exhibit C the Summary of the
Rights to Purchase Preferred Stock) is attached to this Registration Statement
as an exhibit and is incorporated herein by reference.  The foregoing
description of the Rights is qualified in its entirety by reference to the
Rights Agreement and its exhibits.

                                      -3-


ITEM 2.     Exhibits.
            ---------

     The following exhibits are filed as a part hereof:

     3.3  Form of Articles of Amendment to the Company's Articles of
          Incorporation, as amended, creating a new series of Preferred Stock
          designated as Series A Junior Participating Preferred Stock (included
          as Exhibit A to the Rights Agreement).

     4.4  Rights Agreement, dated as of May 16, 2001, between the Company and
          First Union National Bank, as Rights Agent (which includes as (i)
          Exhibit A the form of Articles of Amendment to the Company's Articles
          of Incorporation, as amended, (ii) Exhibit B the form of Rights
          Certificate, and (iii) Exhibit C the Summary of the Rights to Purchase
          Preferred Stock).

     4.5  Form of Rights Certificate (included as Exhibit B to the Rights
          Agreement).

                                      -4-


                                   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.


                                              INSMED INCORPORATED
                                                   (Registrant)



                                By:  /s/ Geoffrey Allan, Ph.D.
                                     -----------------------------------
                                     Geoffrey Allan, Ph.D.
                                     Chairman of the Board, President and Chief
                                     Executive Officer


Dated:  May 17, 2001

                                      -5-


                                 EXHIBIT INDEX



Exhibit No.          Description
--------------     -------------------------------------------------------------

      3.3           Form of Articles of Amendment to the Company's Articles of
                    Incorporation, as amended, creating a new series of
                    Preferred Stock designated as Series A Junior Participating
                    Preferred Stock (included as Exhibit A to the Rights
                    Agreement).

      4.4           Rights Agreement, dated as of May 16, 2001, between the
                    Company and First Union National Bank, as Rights Agent
                    (which includes as (i) Exhibit A the form of Articles of
                    Amendment to the Company's Articles of Incorporation, as
                    amended, (ii) Exhibit B the form of Rights Certificate, and
                    (iii) Exhibit C the Summary of the Rights to Purchase
                    Preferred Stock).

      4.5           Form of Rights Certificate (included as Exhibit B to the
                    Rights Agreement).

                                      -6-