<PAGE>




    As filed with the Securities and Exchange Commission on November 2, 2001
                                                     Registration No. 33- ______

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

                       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        (I.R.S. Employer Identification No.)
   incorporation or organization)

                61 Mooney Street, Cambridge, Massachusetts 02138
               (Address of Principal Executive Offices) (Zip Code)

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

                    ADVANCED MAGNETICS, INC. 1993 STOCK PLAN
                            (Full title of the plan)

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

                                Jerome Goldstein
                Chief Executive Officer, President and Treasurer
                            Advanced Magnetics, Inc.
                                61 Mooney Street
                         Cambridge, Massachusetts 02138
                     (Name and address of agent for service)
                                 (617) 497-2070
          (Telephone number, including area code, of agent for service)

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

                                    Copy to:
                           Sharon Goddard White, Esq.
                             WHITE & MCDERMOTT, P.C.
                                65 William Street
                         Wellesley, Massachusetts 02481
                                 (781) 431-1700

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

                         CALCULATION OF REGISTRATION FEE
<TABLE>
<CAPTION>
                                                                 Proposed
                                             Proposed             maximum
 Title of securities    Amount to be     maximum offering    aggregate offering       Amount of
  to be registered       registered       price per share          price          registration fee
--------------------- ---------------- ------------------- --------------------- ------------------
<S>                   <C>              <C>                 <C>                   <C>
Common Stock,          200,000 shares       $3.425 (1)           $685,000              $171.25
$.01 par value
--------------------- ---------------- ------------------- --------------------- ------------------
</TABLE>


(1) Estimated solely for the purpose of calculating the registration fee
pursuant to Rules 457(c) and 457(h) of the Securities Act of 1933, as amended,
and based upon the average of the high and low prices of the Common Stock on the
American Stock Exchange on October 31, 2001.


<PAGE>


                      STATEMENT UNDER GENERAL INSTRUCTION E
                      REGISTRATION OF ADDITIONAL SECURITIES

     This registration statement on Form S-8 registers additional securities of
the same class as other securities for which a registration statement on Form
S-8 relating to the registrant's 1993 Stock Plan is effective. The registrant's
1993 Stock Plan was amended by resolution of the Board of Directors on December
22, 1998, and approved by the registrant's shareholders on February 2, 1999, to
increase the maximum number of shares of the registrant's $.01 par value Common
Stock which may be issued under the 1993 Stock Plan from 500,000 shares to
700,000 shares. Accordingly, pursuant to General Instruction E to Form S-8, the
registrant hereby incorporates by reference herein the contents of such
registration statement on Form S-8 relating to the registrant's 1993 Stock Plan
filed with the Securities and Exchange Commission on May 11, 1993, File No.
33-62522, and hereby deems such contents to be a part hereof, except as
otherwise updated or modified by this registration statement.



<PAGE>



                                     PART II
               INFORMATION REQUIRED IN THE REGISTRATION STATEMENT

Item 3. INCORPORATION OF DOCUMENTS BY REFERENCE.

     The following documents filed by the registrant with the Securities and
Exchange Commission are hereby incorporated by reference in this registration
statement:

     1. The registrant's Annual Report on Form 10-K for the year ended September
        30, 2000;

     2. The registrant's Current Reports on Form 8-K filed on November 17, 2000
        and April 30, 2001;

     3. The registrant's Quarterly Reports on Form 10-Q for the quarters ended
        December 31, 2000, March 31, 2001 and June 30, 2001; and

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

     In addition, all documents subsequently filed 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 hereby have
been sold or which deregisters all of such securities then remaining unsold,
shall be deemed to be incorporated by reference into this registration statement
and to be a part hereof from the date of filing of such documents.

Item 5. INTERESTS OF NAMED EXPERTS AND COUNSEL

     Legal matters in connection with the issuance of Common Stock offered
hereby have been passed upon for the registrant by White & McDermott, P.C. as
counsel to the registrant. Rachel Goldstein Konforty, an associate of White &
McDermott, P.C., is the Assistant Secretary of the registrant and beneficially
owns less than three percent of the registrant's Common Stock, a portion of
which Ms. Konforty disclaims beneficial ownership and control.

Item 8. EXHIBITS

     The following exhibits are filed as part of this registration statement:

4.1  Certificate of Incorporation of the registrant, as amended (incorporated by
     reference to Exhibit 3.1 to the registrant's Annual Report on Form 10-K for
     the fiscal year ended September 30, 2000, File No. 0-14732).

4.2  By-Laws of the registrant, as amended (incorporated by reference to Exhibit
     3.2 to the registrant's Annual Report on Form 10-K for the fiscal year
     ended September 30, 2000, File No. 0-14732).

<PAGE>


4.3   Specimen certificate representing the registrant's Common Stock
      (incorporated by reference to Exhibit 6 to the Registration Statement on
      Form 8-A of the registrant, Reg. No. 1-10865).

*5.1  Opinion of White & McDermott, P.C. as to the legality of the securities
      being registered.

10.1  1993 Stock Plan, as amended February 2, 1999 (incorporated by reference to
      the exhibits to the registrant's definitive proxy statement for the fiscal
      year ended September 30, 1998, File No. 000-14732).

*23.1 Consent of PricewaterhouseCoopers LLP, independent accountants.

23.2  Consent of White & McDermott, P.C. (included in Exhibit 5.1).

24    Power of Attorney (included in the signature pages of this registration
      statement).

*     Filed herewith.


<PAGE>


                                   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 of the
requirements for filing on Form S-8 and has duly caused this registration
statement to be signed on its behalf by the undersigned, thereunto duly
authorized, in the city of Cambridge, the Commonwealth of Massachusetts, on this
1st day of November, 2001.

                               ADVANCED MAGNETICS, INC.


                               By: /S/ JEROME GOLDSTEIN
                                  ---------------------------------------------
                               Jerome Goldstein, Chairman of the Board,
                               Chief Executive Officer, President and Treasurer


                                POWER OF ATTORNEY

     We, the undersigned officers and directors of Advanced Magnetics, Inc.
hereby severally constitute 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 and in our names in the capacities indicated below,
the registration statement on Form S-8 filed herewith and any and all
pre-effective and post-effective amendments to said registration statement, and
generally to do all such 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, and all requirements of the Securities and
Exchange Commission, hereby ratifying and confirming our signatures as they may
be signed by our said attorneys, or any of them, to said registration statement
and any and all amendments thereto.

     Pursuant to the requirements of the Securities Act of 1933, this
registration statement on Form S-8 has been signed below by the following
persons in the capacities and on the dates indicated.

     SIGNATURE                     TITLE                              DATE


/S/ JEROME GOLDSTEIN      Chairman of the Board,                November 1, 2001
----------------------    Chief Executive Officer, President
Jerome Goldstein          and Treasurer (principal executive
                          and financial officer)


/S/ JAMES A. MATHESON     Vice President - Finance              November 1, 2001
---------------------     (principal accounting officer)
James A. Matheson


<PAGE>


/S/ SHELDON L. BLOCH                Director                    November 1, 2001
---------------------------
Sheldon L. Bloch


/S/ MICHAEL D. LOBERG               Director                    November 1, 2001
---------------------------
Michael D. Loberg


/S/ EDWARD B. ROBERTS               Director                    November 1, 2001
---------------------------
Edward B. Roberts


/S/ GEORGE M. WHITESIDES            Director                    November 1, 2001
------------------------
George M. Whitesides


<PAGE>


                                  EXHIBIT INDEX

EXHIBIT NO.                 DESCRIPTION OF DOCUMENTS

4.1       Certificate of Incorporation of the registrant, as amended
          (incorporated by reference to Exhibit 3.1 to the registrant's Annual
          Report on Form 10-K for the fiscal year ended September 30, 2000, File
          No. 0-14732).

4.2       By-Laws of the registrant, as amended (incorporated by reference to
          Exhibit 3.2 to the registrant's Annual Report on Form 10-K for the
          fiscal year ended September 30, 2000, File No. 0-14732).

4.3       Specimen certificate representing the registrant's Common Stock
          (incorporated by reference to Exhibit 6 to the Registration Statement
          on Form 8-A of the registrant, Reg. No. 1-10865).

*5.1      Opinion of White & McDermott, P.C. as to the legality of the
          securities being registered.

10.1      1993 Stock Plan, as amended February 2, 1999 (incorporated by
          reference to the exhibits to the registrant's definitive proxy
          statement for the fiscal year ended September 30, 1998, File No.
          000-14732).

*23.1    Consent of PricewaterhouseCoopers LLP, independent accountants.

23.2     Consent of White & McDermott, P.C. (included in Exhibit 5.1).

24        Power of Attorney (included in the signature pages of this
          registration statement).

*         Filed herewith.
[{"type": "S-8", "sequence": "1", "filename": "a2062395zs-8.txt", "description": "FORM S-8", "secsgml_size_bytes": 12060}]
{"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": "333-72700", "film-number": "1773736"}, "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"}}
As filed with the Securities and Exchange Commission on November 2, 2001
                                                     Registration No. 33- ______

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

                       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        (I.R.S. Employer Identification No.)
   incorporation or organization)

                61 Mooney Street, Cambridge, Massachusetts 02138
               (Address of Principal Executive Offices) (Zip Code)

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

                    ADVANCED MAGNETICS, INC. 1993 STOCK PLAN
                            (Full title of the plan)

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

                                Jerome Goldstein
                Chief Executive Officer, President and Treasurer
                            Advanced Magnetics, Inc.
                                61 Mooney Street
                         Cambridge, Massachusetts 02138
                     (Name and address of agent for service)
                                 (617) 497-2070
          (Telephone number, including area code, of agent for service)

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

                                    Copy to:
                           Sharon Goddard White, Esq.
                             WHITE & MCDERMOTT, P.C.
                                65 William Street
                         Wellesley, Massachusetts 02481
                                 (781) 431-1700

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

                         CALCULATION OF REGISTRATION FEE
Proposed
                                             Proposed             maximum
 Title of securities    Amount to be     maximum offering    aggregate offering       Amount of
  to be registered       registered       price per share          price          registration fee
--------------------- ---------------- ------------------- --------------------- ------------------
Common Stock,          200,000 shares       $3.425 (1)           $685,000              $171.25
$.01 par value
--------------------- ---------------- ------------------- --------------------- ------------------
(1) Estimated solely for the purpose of calculating the registration fee
pursuant to Rules 457(c) and 457(h) of the Securities Act of 1933, as amended,
and based upon the average of the high and low prices of the Common Stock on the
American Stock Exchange on October 31, 2001.
STATEMENT UNDER GENERAL INSTRUCTION E
                      REGISTRATION OF ADDITIONAL SECURITIES

     This registration statement on Form S-8 registers additional securities of
the same class as other securities for which a registration statement on Form
S-8 relating to the registrant's 1993 Stock Plan is effective. The registrant's
1993 Stock Plan was amended by resolution of the Board of Directors on December
22, 1998, and approved by the registrant's shareholders on February 2, 1999, to
increase the maximum number of shares of the registrant's $.01 par value Common
Stock which may be issued under the 1993 Stock Plan from 500,000 shares to
700,000 shares. Accordingly, pursuant to General Instruction E to Form S-8, the
registrant hereby incorporates by reference herein the contents of such
registration statement on Form S-8 relating to the registrant's 1993 Stock Plan
filed with the Securities and Exchange Commission on May 11, 1993, File No.
33-62522, and hereby deems such contents to be a part hereof, except as
otherwise updated or modified by this registration statement.
PART II
               INFORMATION REQUIRED IN THE REGISTRATION STATEMENT

Item 3. INCORPORATION OF DOCUMENTS BY REFERENCE.

     The following documents filed by the registrant with the Securities and
Exchange Commission are hereby incorporated by reference in this registration
statement:

     1. The registrant's Annual Report on Form 10-K for the year ended September
        30, 2000;

     2. The registrant's Current Reports on Form 8-K filed on November 17, 2000
        and April 30, 2001;

     3. The registrant's Quarterly Reports on Form 10-Q for the quarters ended
        December 31, 2000, March 31, 2001 and June 30, 2001; and

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

     In addition, all documents subsequently filed 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 hereby have
been sold or which deregisters all of such securities then remaining unsold,
shall be deemed to be incorporated by reference into this registration statement
and to be a part hereof from the date of filing of such documents.

Item 5. INTERESTS OF NAMED EXPERTS AND COUNSEL

     Legal matters in connection with the issuance of Common Stock offered
hereby have been passed upon for the registrant by White & McDermott, P.C. as
counsel to the registrant. Rachel Goldstein Konforty, an associate of White &
McDermott, P.C., is the Assistant Secretary of the registrant and beneficially
owns less than three percent of the registrant's Common Stock, a portion of
which Ms. Konforty disclaims beneficial ownership and control.

Item 8. EXHIBITS

     The following exhibits are filed as part of this registration statement:

4.1  Certificate of Incorporation of the registrant, as amended (incorporated by
     reference to Exhibit 3.1 to the registrant's Annual Report on Form 10-K for
     the fiscal year ended September 30, 2000, File No. 0-14732).

4.2  By-Laws of the registrant, as amended (incorporated by reference to Exhibit
     3.2 to the registrant's Annual Report on Form 10-K for the fiscal year
     ended September 30, 2000, File No. 0-14732).
4.3   Specimen certificate representing the registrant's Common Stock
      (incorporated by reference to Exhibit 6 to the Registration Statement on
      Form 8-A of the registrant, Reg. No. 1-10865).

*5.1  Opinion of White & McDermott, P.C. as to the legality of the securities
      being registered.

10.1  1993 Stock Plan, as amended February 2, 1999 (incorporated by reference to
      the exhibits to the registrant's definitive proxy statement for the fiscal
      year ended September 30, 1998, File No. 000-14732).

*23.1 Consent of PricewaterhouseCoopers LLP, independent accountants.

23.2  Consent of White & McDermott, P.C. (included in Exhibit 5.1).

24    Power of Attorney (included in the signature pages of this registration
      statement).

*     Filed herewith.
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 of the
requirements for filing on Form S-8 and has duly caused this registration
statement to be signed on its behalf by the undersigned, thereunto duly
authorized, in the city of Cambridge, the Commonwealth of Massachusetts, on this
1st day of November, 2001.

                               ADVANCED MAGNETICS, INC.

                               By: /S/ JEROME GOLDSTEIN
                                  ---------------------------------------------
                               Jerome Goldstein, Chairman of the Board,
                               Chief Executive Officer, President and Treasurer

                                POWER OF ATTORNEY

     We, the undersigned officers and directors of Advanced Magnetics, Inc.
hereby severally constitute 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 and in our names in the capacities indicated below,
the registration statement on Form S-8 filed herewith and any and all
pre-effective and post-effective amendments to said registration statement, and
generally to do all such 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, and all requirements of the Securities and
Exchange Commission, hereby ratifying and confirming our signatures as they may
be signed by our said attorneys, or any of them, to said registration statement
and any and all amendments thereto.

     Pursuant to the requirements of the Securities Act of 1933, this
registration statement on Form S-8 has been signed below by the following
persons in the capacities and on the dates indicated.

     SIGNATURE                     TITLE                              DATE

/S/ JEROME GOLDSTEIN      Chairman of the Board,                November 1, 2001
----------------------    Chief Executive Officer, President
Jerome Goldstein          and Treasurer (principal executive
                          and financial officer)

/S/ JAMES A. MATHESON     Vice President - Finance              November 1, 2001
---------------------     (principal accounting officer)
James A. Matheson
/S/ SHELDON L. BLOCH                Director                    November 1, 2001
---------------------------
Sheldon L. Bloch

/S/ MICHAEL D. LOBERG               Director                    November 1, 2001
---------------------------
Michael D. Loberg

/S/ EDWARD B. ROBERTS               Director                    November 1, 2001
---------------------------
Edward B. Roberts

/S/ GEORGE M. WHITESIDES            Director                    November 1, 2001
------------------------
George M. Whitesides
EXHIBIT INDEX

EXHIBIT NO.                 DESCRIPTION OF DOCUMENTS

4.1       Certificate of Incorporation of the registrant, as amended
          (incorporated by reference to Exhibit 3.1 to the registrant's Annual
          Report on Form 10-K for the fiscal year ended September 30, 2000, File
          No. 0-14732).

4.2       By-Laws of the registrant, as amended (incorporated by reference to
          Exhibit 3.2 to the registrant's Annual Report on Form 10-K for the
          fiscal year ended September 30, 2000, File No. 0-14732).

4.3       Specimen certificate representing the registrant's Common Stock
          (incorporated by reference to Exhibit 6 to the Registration Statement
          on Form 8-A of the registrant, Reg. No. 1-10865).

*5.1      Opinion of White & McDermott, P.C. as to the legality of the
          securities being registered.

10.1      1993 Stock Plan, as amended February 2, 1999 (incorporated by
          reference to the exhibits to the registrant's definitive proxy
          statement for the fiscal year ended September 30, 1998, File No.
          000-14732).

*23.1    Consent of PricewaterhouseCoopers LLP, independent accountants.

23.2     Consent of White & McDermott, P.C. (included in Exhibit 5.1).

24        Power of Attorney (included in the signature pages of this
          registration statement).

*         Filed herewith.