<PAGE>   1
      As filed with the Securities and Exchange Commission on June 3, 1997.

                                                        Registration No. 333-

================================================================================

                       SECURITIES AND EXCHANGE COMMISSION
                             WASHINGTON, D.C. 20549

                              --------------------
                                    FORM S-8
                          REGISTRATION STATEMENT UNDER
                           THE SECURITIES ACT OF 1933

                              --------------------
                            ADVANCED MAGNETICS, INC.
             (Exact name of registrant as specified in its charter)

<TABLE>
<S>                                                                           <C>
                           Delaware                                                        04-2742593
(State or other jurisdiction of incorporation or organization)                (I.R.S. Employer Identification No.)
</TABLE>

                               725 Concord Avenue
                         Cambridge, Massachusetts 02138
                                 (617) 354-3929
               (Address of Principal Executive Offices) (Zip Code)

                              --------------------
                        1997 Employee Stock Purchase Plan
                            (Full title of the plans)

                              --------------------
                                Jerome Goldstein
                 Chairman of the Board, President and Treasurer
                            Advanced Magnetics, Inc.
                               725 Concord Avenue
                         Cambridge, Massachusetts 02138
                                 (617) 354-3929

           (Name and address including zip code and telephone number,
                   including area code, of agent for service)

                              --------------------
                                    Copy to:
                              Leslie E. Davis, Esq.
                         TESTA, HURWITZ & THIBEAULT, LLP
                       High Street Tower, 125 High Street
                           Boston, Massachusetts 02110
                                 (617) 248-7000

     Approximate date of commencement of proposed sale to the public: As soon as
practicable after this Registration Statement becomes effective.

                              --------------------
<TABLE>
                                          CALCULATION OF REGISTRATION FEE
<CAPTION>
===============================================================================================================

                                                              Proposed           Proposed
                                                              Maximum             Maximum
             Title of                       Amount            Offering           Aggregate          Amount of
          Securities to                      to be           Price Per           Offering         Registration
          be Registered                   Registered           Share               Price               Fee
---------------------------------------------------------------------------------------------------------------
<S>                                        <C>                <C>               <C>                  <C>    
1997 EMPLOYEE STOCK PURCHASE PLAN
Common Stock (Par Value $.01)              150,000            $12.00(1)         $1,800,000           $545.45

---------------------------------------------------------------------------------------------------------------
</TABLE>
(1) The price of $12.00 per share, which is the average of the high and low
prices of the common stock of the registrant reported on the Nasdaq National
Market on May 27, 1997, is set forth solely for purposes of calculating the
filing fee pursuant to Rule 457(c) and (h).


<PAGE>   2


                                       -2-


                                     PART I

              INFORMATION REQUIRED IN THE SECTION 10(a) PROSPECTUS


Item 1.   PLAN INFORMATION.

         The documents containing the information specified in this Item 1 will
be sent or given to employees, directors or others as specified by Rule
428(b)(1). In accordance with the rules and regulations of the Securities and
Exchange Commission (the "Commission") and the instructions to Form S-8, such
documents are not being filed with the Commission either as part of this
Registration Statement or as prospectuses or prospectus supplements pursuant to
Rule 424.

Item 2.   REGISTRANT INFORMATION AND EMPLOYEE PLAN ANNUAL INFORMATION.

         The documents containing the information specified in this Item 2 will
be sent or given to employees as specified by Rule 428(b)(1). In accordance with
the rules and regulations of the Commission and the instructions to Form S-8,
such documents are not being filed with the Commission either as part of this
Registration Statement or as prospectuses or prospectus supplements pursuant to
Rule 424.

                                     PART II

               INFORMATION REQUIRED IN THE REGISTRATION STATEMENT


Item 3.   INCORPORATION OF DOCUMENTS BY REFERENCE.

         The following documents filed with the Commission are incorporated by
reference in this Registration Statement:

         (a)      Registrant's Annual Report on Form 10-K for the year ended
                  September 30, 1996;

         (b)      Registrant's Quarterly Report on Form 10-Q for the quarter
                  ended December 31, 1996;

         (c)      Registrant's Quarterly Report on Form 10-Q for the quarter
                  ended March 31, 1997; and

         (d)      The section entitled "Description of Registrant's Securities
                  to be Registered," contained in the Company's Registration
                  Statement No. 0-14732 on Form 8-A filed pursuant to Section
                  12(g) of the Exchange Act.

         All documents subsequently filed with the Commission by the Registrant
pursuant to Sections 13(a), 13(c), 14 and 15(d) of the Exchange Act, prior to
the filing of a post-effective amendment which indicates that all securities
offered herein have been sold or which deregisters 


<PAGE>   3
                                      -3-


all securities then remaining unsold, shall be deemed to be incorporated by
reference in this Registration Statement and to be a part hereof from the date
of filing of such documents.



Item 4.   DESCRIPTION OF SECURITIES.

         Not applicable.

Item 5.   INTEREST OF NAMED EXPERTS AND COUNSEL.

         Not applicable.

Item 6.   INDEMNIFICATION OF DIRECTORS AND OFFICERS.

         Section 145 of the General Corporation Law of Delaware empowers a
corporation to indemnify any person who was or is a party or is threatened to be
made a party to any threatened, pending or completed action, suit or proceeding,
whether civil, criminal, administrative or investigative, by reason of the fact
that the or she is or was a director, officer, employee or agent of the
corporation or another enterprise if serving at the request of the corporation.
Depending on the character of the proceeding, a corporation may indemnify
against expenses (including attorney's fees), judgments, fines and amounts paid
in settlement actually and reasonably incurred in connection with such action,
suit or proceeding if the person indemnified acted in good faith and in a manner
he or she reasonably believed to be in or not opposed to the best interests of
the corporation, and, with respect to any criminal action or proceeding, had no
reasonable cause to believe his or her conduct was unlawful. In the case of an
action by or in the right of the corporation, no indemnification may be made in
respect to any claim, issue or matter as to which such person shall have been
adjudged to be liable to the corporation unless and only to the extent that the
Court of Chancery or the court in which such action or suit was brought shall
determine that despite the adjudication of liability, but in view of all the
circumstances of the case, such person is fairly and reasonably entitled to
indemnity for such expenses that the court shall deem proper. Section 145
further provides that to the extent a director or officer of a corporation has
been successful in the defense of any action, suit or proceeding referred to
above, or in defense of any claim, issue or matter therein, he or she shall be
indemnified against expenses (including attorney's fees) actually and reasonably
incurred by him or her in connection therewith.

         The Registrant's Certificate of Incorporation provides that the
Registrant shall, to the fullest extent permitted by law, indemnify all
directors, officers, employees and agents of the company. The Certificate of
Incorporation also contains a provision eliminating the liability of directors
of the Registrant to the Registrant or its stockholders for monetary damage,
except under certain circumstances. The Certificate of Incorporation also
permits the Registrant to maintain insurance to protect itself and any director,
officer, employee or agent against any liability with respect to which the
Corporation would have the power to indemnify such persons under the Delaware
General Corporation Law. The Registrant maintains an insurance policy insuring
its directors and officers against certain liabilities.



<PAGE>   4
                                      -4-


Item 7.  EXEMPTION FROM REGISTRATION CLAIMED.

         Not applicable.

Item 8.  EXHIBITS.

     Exhibit
     Number                              Description
     -------    ----------------------------------------------------------------

      4.1(1)    Certificate of Incorporation of the Company, as amended.

      4.2(2)    By-Laws of the Company, as amended.

      4.3(3)    1992 Non-Employee Director Stock Option Plan.

      4.4(4)    1993 Stock Plan.

      4.5(4)    1993 Non-Employee Director Stock Option Plan.

      4.6(5)    1997 Employee Stock Purchase Plan.

      5.1       Opinion of Testa, Hurwitz & Thibeault, LLP.

     23.1       Consent of Coopers & Lybrand L.L.P, independent accountants.

     23.2       Consent of Testa, Hurwitz & Thibeault, LLP (see Exhibit 5.1).

     24.1       Power of Attorney (see Page 7).

  (1) Incorporated herein by reference to the exhibits to the Company's
  Registration Statement on Form S-1, as amended (File No. 33-5312).

  (2) Incorporated herein by reference to the exhibits to the Company's Annual
  Report on Form 10-K for the fiscal year ended September 30, 1987.

  (3) Incorporated herein by reference to the exhibits to the Company's Annual
  Report on Form 10-K for the fiscal year ended September 30, 1991.

  (4) Incorporated herein by reference to the exhibits to the Company's
  definitive proxy statement for the fiscal year ended September 30, 1992.

  (5) Incorporated herein by reference to the exhibits to the Company's
  definitive Proxy Statement for the fiscal year ended September 30, 1996.

Item 9.  UNDERTAKINGS.

         (a)      The undersigned registrant hereby undertakes:

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

<PAGE>   5
                                      -5-


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

                           (ii)     To reflect in the prospectus any facts or
                                    events arising after the effective date of
                                    the Registration Statement (or the most
                                    recent post-effective amendment thereof)
                                    which, individually or in the aggregate,
                                    represent a fundamental change in the
                                    information set forth in the Registration
                                    Statement;

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

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

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

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

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

         (c)      Insofar as indemnification for liabilities arising under the
                  Securities Act of 1933 may be permitted to directors, officers
                  and controlling persons of the Registrant pursuant to the
                  foregoing provisions, or otherwise, the Registrant has been
                  advised that in the opinion of the Securities and Exchange
                  Commission such indemnification is against public policy as
                  expressed in the Securities Act of 1933 and is, therefore,
                  unenforceable. In the event that a claim for indemnification
                  against such liabilities (other than the payment by the
                  Registrant 

<PAGE>   6
                                      -6-


                  of expenses incurred or paid by a director, officer or
                  controlling person of the Registrant in the successful defense
                  of any action, suit or proceeding) is asserted by such
                  director, officer or controlling person in connection with the
                  securities being registered, the Registrant will, unless in
                  the opinion of its counsel the matter has been settled by
                  controlling precedent, submit to a court of appropriate
                  jurisdiction the question whether such indemnification by it
                  is against public policy as expressed in the Act and will be
                  governed by the final adjudication of such issue.

                           [REMAINDER OF PAGE INTENTIONALLY LEFT BLANK]




<PAGE>   7
                                      -7-


                                   SIGNATURES

         Pursuant to the requirements of the Securities Act of 1933, the
registrant certifies that it has reasonable grounds to believe that it meets all
the requirements for filing on Form S-8 and has duly caused this registration
statement to be signed on its behalf by the undersigned, thereunto duly
authorized, in Cambridge, Massachusetts on June 3, 1997.

                                  ADVANCED MAGNETICS, INC.

                                  By:  /s/ Jerome Goldstein
                                      ------------------------------------------
                                      Jerome Goldstein, Chairman of the Board of
                                      Directors, President and Treasurer

                                POWER OF ATTORNEY

         We, the undersigned officers and directors of Advanced Magnetics, Inc.
hereby severally constitute and appoint Jerome Goldstein and James A. Matheson,
and each of them singly, our true and lawful attorneys, with full power to them
and each of them singly, to sign for us in our names in the capacities indicated
below, any amendments to this Registration Statement on Form S-8 (including
post-effective amendments), and to file the same, with all exhibits thereto and
other documents in connection therewith, with the Securities and Exchange
Commission, and generally to do all things in our names and on our behalf in our
capacities as officers and directors to enable Advanced Magnetics, Inc. to
comply with the provisions of the Securities Act of 1933, as amended, hereby
ratifying and confirming our signatures as they may be signed by our said
attorneys, or any of them, to said Registration Statement and all amendments
thereto.

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

<TABLE>
<CAPTION>
          Signature                           Title(s)                             Date
          ---------                           --------                             ----


<S>                               <C>                                           <C>
/s/ Jerome Goldstein              Chairman of the Board of Directors,           June 3, 1997
-----------------------------     President and Treasurer (principal
Jerome Goldstein                  executive and financial officer)


/s/ James A. Matheson             Vice President-Finance (principal             June 3, 1997
-----------------------------     accounting officer)
James A. Matheson                           


/s/ Leonard M. Baum               Director                                      June 3, 1997
-----------------------------     
Leonard M. Baum
</TABLE>


<PAGE>   8
                                      -8-


<TABLE>
<CAPTION>
       Signature                           Title(s)                                  Date
       ---------                           --------                                  ----


<S>                               <C>                                           <C>

/s/ Thomas Coor                   Director                                      June 3, 1997
-----------------------------
Thomas Coor


/s/ Leslie Goldstein              Director                                      June 3, 1997
-----------------------------
Leslie Goldstein

                                  Director                                      June 3, 1997
-----------------------------
Michael Loberg

/s/ Richard L. McIntire           Director                                      June 3, 1997
-----------------------------
Richard L. McIntire


/s/ Edward B. Roberts             Director                                      June 3, 1997
-----------------------------
Edward B. Roberts


/s/ Roger E. Travis               Director                                      June 3, 1997
-----------------------------
Roger E. Travis


/s/ George M. Whitesides          Director                                      June 3, 1997
-----------------------------
George M. Whitesides
</TABLE>



<PAGE>   9



                                  Exhibit Index
                                  -------------

   Exhibit
   Number                           Description                             Page
   -------   -------------------------------------------------------------  ----

    4.1(1)   Certificate of Incorporation of the Company, as amended.

    4.2(2)   By-Laws of the Company, as amended.

    4.3(3)   1992 Non-Employee Director Stock Option Plan.

    4.4(4)   1993 Stock Plan.

    4.5(4)   1993 Non-Employee Director Stock Option Plan.

    4.6(5)   1997 Employee Stock Purchase Plan.

    5.1      Opinion of Testa, Hurwitz & Thibeault, LLP.

   23.1      Consent of Coopers & Lybrand L.L.P, independent accountants.

   23.2      Consent of Testa, Hurwitz & Thibeault, LLP (see Exhibit 5.1).

   24.1      Power of Attorney (see Page 7).

   (1) Incorporated herein by reference to the exhibits to the Company's
   Registration Statement on Form S-1, as amended (File No. 33-5312).

   (2) Incorporated herein by reference to the exhibits to the Company's Annual
   Report on Form 10-K for the fiscal year ended September 30, 1987.

   (3) Incorporated herein by reference to the exhibits to the Company's Annual
   Report on Form 10-K for the fiscal year ended September 30, 1991.

   (4) Incorporated herein by reference to the exhibits to the Company's
   definitive proxy statement for the fiscal year ended September 30, 1992.

   (5) Incorporated herein by reference to the exhibits to the Company's
   definitive Proxy Statement for the fiscal year ended September 30, 1996.
[{"type": "S-8", "sequence": "1", "description": "ADVANCED MAGNETICS, INC.", "secsgml_size_bytes": 22572}]
{"company-data": {"conformed-name": "ADVANCED MAGNETICS INC", "cik": "0000792977", "assigned-sic": "2835", "irs-number": "042742593", "state-of-incorporation": "DE", "fiscal-year-end": "0930"}, "filing-values": {"form-type": "S-8", "act": "33", "file-number": "333-28417", "film-number": "97618657"}, "business-address": {"street1": "61 MOONEY ST", "city": "CAMBRIDGE", "state": "MA", "zip": "02138", "phone": "6173543929"}, "mail-address": {"street1": "61 MOONEY ST", "city": "CAMBRIDGE", "state": "MA", "zip": "02138"}}
1
      As filed with the Securities and Exchange Commission on June 3, 1997.

                                                        Registration No. 333-

================================================================================

                       SECURITIES AND EXCHANGE COMMISSION
                             WASHINGTON, D.C. 20549

                              --------------------
                                    FORM S-8
                          REGISTRATION STATEMENT UNDER
                           THE SECURITIES ACT OF 1933

                              --------------------
                            ADVANCED MAGNETICS, INC.
             (Exact name of registrant as specified in its charter)
Delaware                                                        04-2742593
(State or other jurisdiction of incorporation or organization)                (I.R.S. Employer Identification No.)
725 Concord Avenue
                         Cambridge, Massachusetts 02138
                                 (617) 354-3929
               (Address of Principal Executive Offices) (Zip Code)

                              --------------------
                        1997 Employee Stock Purchase Plan
                            (Full title of the plans)

                              --------------------
                                Jerome Goldstein
                 Chairman of the Board, President and Treasurer
                            Advanced Magnetics, Inc.
                               725 Concord Avenue
                         Cambridge, Massachusetts 02138
                                 (617) 354-3929

           (Name and address including zip code and telephone number,
                   including area code, of agent for service)

                              --------------------
                                    Copy to:
                              Leslie E. Davis, Esq.
                         TESTA, HURWITZ & THIBEAULT, LLP
                       High Street Tower, 125 High Street
                           Boston, Massachusetts 02110
                                 (617) 248-7000

     Approximate date of commencement of proposed sale to the public: As soon as
practicable after this Registration Statement becomes effective.

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

                                          CALCULATION OF REGISTRATION FEE
===============================================================================================================

                                                              Proposed           Proposed
                                                              Maximum             Maximum
             Title of                       Amount            Offering           Aggregate          Amount of
          Securities to                      to be           Price Per           Offering         Registration
          be Registered                   Registered           Share               Price               Fee
---------------------------------------------------------------------------------------------------------------
1997 EMPLOYEE STOCK PURCHASE PLAN
Common Stock (Par Value $.01)              150,000            $12.00(1)         $1,800,000           $545.45

---------------------------------------------------------------------------------------------------------------
(1) The price of $12.00 per share, which is the average of the high and low
prices of the common stock of the registrant reported on the Nasdaq National
Market on May 27, 1997, is set forth solely for purposes of calculating the
filing fee pursuant to Rule 457(c) and (h).
2

                                       -2-

                                     PART I

              INFORMATION REQUIRED IN THE SECTION 10(a) PROSPECTUS

Item 1.   PLAN INFORMATION.

         The documents containing the information specified in this Item 1 will
be sent or given to employees, directors or others as specified by Rule
428(b)(1). In accordance with the rules and regulations of the Securities and
Exchange Commission (the "Commission") and the instructions to Form S-8, such
documents are not being filed with the Commission either as part of this
Registration Statement or as prospectuses or prospectus supplements pursuant to
Rule 424.

Item 2.   REGISTRANT INFORMATION AND EMPLOYEE PLAN ANNUAL INFORMATION.

         The documents containing the information specified in this Item 2 will
be sent or given to employees as specified by Rule 428(b)(1). In accordance with
the rules and regulations of the Commission and the instructions to Form S-8,
such documents are not being filed with the Commission either as part of this
Registration Statement or as prospectuses or prospectus supplements pursuant to
Rule 424.

                                     PART II

               INFORMATION REQUIRED IN THE REGISTRATION STATEMENT

Item 3.   INCORPORATION OF DOCUMENTS BY REFERENCE.

         The following documents filed with the Commission are incorporated by
reference in this Registration Statement:

         (a)      Registrant's Annual Report on Form 10-K for the year ended
                  September 30, 1996;

         (b)      Registrant's Quarterly Report on Form 10-Q for the quarter
                  ended December 31, 1996;

         (c)      Registrant's Quarterly Report on Form 10-Q for the quarter
                  ended March 31, 1997; and

         (d)      The section entitled "Description of Registrant's Securities
                  to be Registered," contained in the Company's Registration
                  Statement No. 0-14732 on Form 8-A filed pursuant to Section
                  12(g) of the Exchange Act.

         All documents subsequently filed with the Commission by the Registrant
pursuant to Sections 13(a), 13(c), 14 and 15(d) of the Exchange Act, prior to
the filing of a post-effective amendment which indicates that all securities
offered herein have been sold or which deregisters
3
                                      -3-

all securities then remaining unsold, shall be deemed to be incorporated by
reference in this Registration Statement and to be a part hereof from the date
of filing of such documents.

Item 4.   DESCRIPTION OF SECURITIES.

         Not applicable.

Item 5.   INTEREST OF NAMED EXPERTS AND COUNSEL.

         Not applicable.

Item 6.   INDEMNIFICATION OF DIRECTORS AND OFFICERS.

         Section 145 of the General Corporation Law of Delaware empowers a
corporation to indemnify any person who was or is a party or is threatened to be
made a party to any threatened, pending or completed action, suit or proceeding,
whether civil, criminal, administrative or investigative, by reason of the fact
that the or she is or was a director, officer, employee or agent of the
corporation or another enterprise if serving at the request of the corporation.
Depending on the character of the proceeding, a corporation may indemnify
against expenses (including attorney's fees), judgments, fines and amounts paid
in settlement actually and reasonably incurred in connection with such action,
suit or proceeding if the person indemnified acted in good faith and in a manner
he or she reasonably believed to be in or not opposed to the best interests of
the corporation, and, with respect to any criminal action or proceeding, had no
reasonable cause to believe his or her conduct was unlawful. In the case of an
action by or in the right of the corporation, no indemnification may be made in
respect to any claim, issue or matter as to which such person shall have been
adjudged to be liable to the corporation unless and only to the extent that the
Court of Chancery or the court in which such action or suit was brought shall
determine that despite the adjudication of liability, but in view of all the
circumstances of the case, such person is fairly and reasonably entitled to
indemnity for such expenses that the court shall deem proper. Section 145
further provides that to the extent a director or officer of a corporation has
been successful in the defense of any action, suit or proceeding referred to
above, or in defense of any claim, issue or matter therein, he or she shall be
indemnified against expenses (including attorney's fees) actually and reasonably
incurred by him or her in connection therewith.

         The Registrant's Certificate of Incorporation provides that the
Registrant shall, to the fullest extent permitted by law, indemnify all
directors, officers, employees and agents of the company. The Certificate of
Incorporation also contains a provision eliminating the liability of directors
of the Registrant to the Registrant or its stockholders for monetary damage,
except under certain circumstances. The Certificate of Incorporation also
permits the Registrant to maintain insurance to protect itself and any director,
officer, employee or agent against any liability with respect to which the
Corporation would have the power to indemnify such persons under the Delaware
General Corporation Law. The Registrant maintains an insurance policy insuring
its directors and officers against certain liabilities.
4
                                      -4-

Item 7.  EXEMPTION FROM REGISTRATION CLAIMED.

         Not applicable.

Item 8.  EXHIBITS.

     Exhibit
     Number                              Description
     -------    ----------------------------------------------------------------

      4.1(1)    Certificate of Incorporation of the Company, as amended.

      4.2(2)    By-Laws of the Company, as amended.

      4.3(3)    1992 Non-Employee Director Stock Option Plan.

      4.4(4)    1993 Stock Plan.

      4.5(4)    1993 Non-Employee Director Stock Option Plan.

      4.6(5)    1997 Employee Stock Purchase Plan.

      5.1       Opinion of Testa, Hurwitz & Thibeault, LLP.

     23.1       Consent of Coopers & Lybrand L.L.P, independent accountants.

     23.2       Consent of Testa, Hurwitz & Thibeault, LLP (see Exhibit 5.1).

     24.1       Power of Attorney (see Page 7).

  (1) Incorporated herein by reference to the exhibits to the Company's
  Registration Statement on Form S-1, as amended (File No. 33-5312).

  (2) Incorporated herein by reference to the exhibits to the Company's Annual
  Report on Form 10-K for the fiscal year ended September 30, 1987.

  (3) Incorporated herein by reference to the exhibits to the Company's Annual
  Report on Form 10-K for the fiscal year ended September 30, 1991.

  (4) Incorporated herein by reference to the exhibits to the Company's
  definitive proxy statement for the fiscal year ended September 30, 1992.

  (5) Incorporated herein by reference to the exhibits to the Company's
  definitive Proxy Statement for the fiscal year ended September 30, 1996.

Item 9.  UNDERTAKINGS.

         (a)      The undersigned registrant hereby undertakes:

                  (1)      To file, during any period in which offers or sales
                           are being made, a post-effective amendment to this
                           Registration Statement:
5
                                      -5-

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

                           (ii)     To reflect in the prospectus any facts or
                                    events arising after the effective date of
                                    the Registration Statement (or the most
                                    recent post-effective amendment thereof)
                                    which, individually or in the aggregate,
                                    represent a fundamental change in the
                                    information set forth in the Registration
                                    Statement;

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

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

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

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

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

         (c)      Insofar as indemnification for liabilities arising under the
                  Securities Act of 1933 may be permitted to directors, officers
                  and controlling persons of the Registrant pursuant to the
                  foregoing provisions, or otherwise, the Registrant has been
                  advised that in the opinion of the Securities and Exchange
                  Commission such indemnification is against public policy as
                  expressed in the Securities Act of 1933 and is, therefore,
                  unenforceable. In the event that a claim for indemnification
                  against such liabilities (other than the payment by the
                  Registrant
6
                                      -6-

                  of expenses incurred or paid by a director, officer or
                  controlling person of the Registrant in the successful defense
                  of any action, suit or proceeding) is asserted by such
                  director, officer or controlling person in connection with the
                  securities being registered, the Registrant will, unless in
                  the opinion of its counsel the matter has been settled by
                  controlling precedent, submit to a court of appropriate
                  jurisdiction the question whether such indemnification by it
                  is against public policy as expressed in the Act and will be
                  governed by the final adjudication of such issue.

                           [REMAINDER OF PAGE INTENTIONALLY LEFT BLANK]
7
                                      -7-

                                   SIGNATURES

         Pursuant to the requirements of the Securities Act of 1933, the
registrant certifies that it has reasonable grounds to believe that it meets all
the requirements for filing on Form S-8 and has duly caused this registration
statement to be signed on its behalf by the undersigned, thereunto duly
authorized, in Cambridge, Massachusetts on June 3, 1997.

                                  ADVANCED MAGNETICS, INC.

                                  By:  /s/ Jerome Goldstein
                                      ------------------------------------------
                                      Jerome Goldstein, Chairman of the Board of
                                      Directors, President and Treasurer

                                POWER OF ATTORNEY

         We, the undersigned officers and directors of Advanced Magnetics, Inc.
hereby severally constitute and appoint Jerome Goldstein and James A. Matheson,
and each of them singly, our true and lawful attorneys, with full power to them
and each of them singly, to sign for us in our names in the capacities indicated
below, any amendments to this Registration Statement on Form S-8 (including
post-effective amendments), and to file the same, with all exhibits thereto and
other documents in connection therewith, with the Securities and Exchange
Commission, and generally to do all things in our names and on our behalf in our
capacities as officers and directors to enable Advanced Magnetics, Inc. to
comply with the provisions of the Securities Act of 1933, as amended, hereby
ratifying and confirming our signatures as they may be signed by our said
attorneys, or any of them, to said Registration Statement and all amendments
thereto.

         Pursuant to the requirements of the Securities Act of 1933, this
Registration Statement has been signed by the following persons in the
capacities and on the dates indicated.
Signature                           Title(s)                             Date
          ---------                           --------                             ----
/s/ Jerome Goldstein              Chairman of the Board of Directors,           June 3, 1997
-----------------------------     President and Treasurer (principal
Jerome Goldstein                  executive and financial officer)

/s/ James A. Matheson             Vice President-Finance (principal             June 3, 1997
-----------------------------     accounting officer)
James A. Matheson                           

/s/ Leonard M. Baum               Director                                      June 3, 1997
-----------------------------     
Leonard M. Baum
8
                                      -8-
Signature                           Title(s)                                  Date
       ---------                           --------                                  ----
/s/ Thomas Coor                   Director                                      June 3, 1997
-----------------------------
Thomas Coor

/s/ Leslie Goldstein              Director                                      June 3, 1997
-----------------------------
Leslie Goldstein

                                  Director                                      June 3, 1997
-----------------------------
Michael Loberg

/s/ Richard L. McIntire           Director                                      June 3, 1997
-----------------------------
Richard L. McIntire

/s/ Edward B. Roberts             Director                                      June 3, 1997
-----------------------------
Edward B. Roberts

/s/ Roger E. Travis               Director                                      June 3, 1997
-----------------------------
Roger E. Travis

/s/ George M. Whitesides          Director                                      June 3, 1997
-----------------------------
George M. Whitesides
9

                                  Exhibit Index
                                  -------------

   Exhibit
   Number                           Description                             Page
   -------   -------------------------------------------------------------  ----

    4.1(1)   Certificate of Incorporation of the Company, as amended.

    4.2(2)   By-Laws of the Company, as amended.

    4.3(3)   1992 Non-Employee Director Stock Option Plan.

    4.4(4)   1993 Stock Plan.

    4.5(4)   1993 Non-Employee Director Stock Option Plan.

    4.6(5)   1997 Employee Stock Purchase Plan.

    5.1      Opinion of Testa, Hurwitz & Thibeault, LLP.

   23.1      Consent of Coopers & Lybrand L.L.P, independent accountants.

   23.2      Consent of Testa, Hurwitz & Thibeault, LLP (see Exhibit 5.1).

   24.1      Power of Attorney (see Page 7).

   (1) Incorporated herein by reference to the exhibits to the Company's
   Registration Statement on Form S-1, as amended (File No. 33-5312).

   (2) Incorporated herein by reference to the exhibits to the Company's Annual
   Report on Form 10-K for the fiscal year ended September 30, 1987.

   (3) Incorporated herein by reference to the exhibits to the Company's Annual
   Report on Form 10-K for the fiscal year ended September 30, 1991.

   (4) Incorporated herein by reference to the exhibits to the Company's
   definitive proxy statement for the fiscal year ended September 30, 1992.

   (5) Incorporated herein by reference to the exhibits to the Company's
   definitive Proxy Statement for the fiscal year ended September 30, 1996.