Exhibit 32.1

CERTIFICATION PURSUANT TO
18 U.S.C. SECTION 1350,
AS ADOPTED PURSUANT TO
SECTION 906 OF THE SARBANES-OXLEY ACT OF 2002

In connection with the Quarterly Report of Advanced Magnetics, Inc. (the “Company”) on Form 10-Q for the period ended June 30, 2005 as filed with the Securities and Exchange Commission on the date hereof (the “Report”), I, Jerome Goldstein, Chairman of the Board of Directors, Chief Executive Officer, President and Treasurer of the Company, certify, pursuant to 18 U.S.C. § 1350, as adopted pursuant to § 906 of the Sarbanes-Oxley Act of 2002, that to my knowledge:

(1)The Report fully complies with the requirements of Section 13(a) or 15(d) of the Securities Exchange Act of 1934; and

(2)The information contained in the Report fairly presents, in all material respects, the financial condition and results of operations of the Company.

/s/  Jerome Goldstein

Jerome Goldstein

Chairman of the Board of Directors,

Chief Executive Officer, President

and Treasurer

August 12, 2005