Amgen Announces $800 Million Investment In Juncos, Puerto Rico For Biotech Manufacturing Center

SITE DEVELOPMENT COULD CREATE 600 NEW JOBS OVER THE NEXT FOUR YEARS

SITE DEVELOPMENT COULD CREATE 600 NEW JOBS OVER THE NEXT FOUR YEARS

AMGEN EMPLOYS 1,300 ADDITIONAL WORKERS FOR CONSTRUCTION PROJECT

For Immediate Release

Juncos, Puerto Rico. - March 20, 2003 - Amgen (Nasdaq: AMGN), the world's largest biotechnology company, announced its plans to invest $800 million over the next three to five years to create a biotechnology center for bulk manufacturing in Juncos, Puerto Rico. The site will include manufacturing plants for key biologics, full testing quality analytical laboratories, a new syringe line facility, high-speed packaging capability, warehouses and administration buildings. The announcement was made by Kevin Sharer, Amgen's chairman and chief executive officer, at the Juncos site.

Sharer said, "Amgen is committed to Puerto Rico for many reasons, including the quality of the people in the region, the existing business climate, Amgen's 10-year track record in Juncos, the outstanding quality and compliance record the site has achieved, and the excellent relationship Amgen has experienced with the government, the community, and academia." Sharer said that Amgen is growing worldwide, and the increased demand for new and existing Amgen products requires that the company build these new facilities.

It is anticipated that the new center will create jobs for about 600 people over the next four years, increasing Amgen's workforce here to about 1,000 people. The current construction project now employs approximately 1,300. Worldwide, Amgen has more than 10,000 staff members.

To help ensure the successful recruitment and education of staff over the next several years, Amgen has donated $100,000 for The Amgen Biotechnology Learning Center at the University of Puerto Rico Mayagüez Campus (RUM). The center will be available to undergraduate students, high school teachers and professionals.

The $800 million investment announced today was included in Amgen's December 12, 2002 guidance of a total of $1.3 to $1.5 billion for capital spending projects for 2003.

Amgen is a global biotechnology company that discovers, develops, manufactures and markets important human therapeutics based on advances in cellular and molecular biology.

Forward-Looking Statements

This news release contains forward-looking statements that involve significant risks and uncertainties, including those discussed below and more fully described in the Securities and Exchange Commission reports filed by Amgen, including our most recent Form 10-K, and actual results could differ materially from those described. All statements other than statements of historical fact are statements that could be deemed forward-looking statements, including estimates of sales, growth rates, earning per share, revenues, operation margins, tax rate, expenditures and other financial metrics, expected regulatory or clinical results, and other future estimates and results. Amgen conducts research in the biotechnology/pharmaceutical field where movement from concept to product is uncertain; consequently, there can be no guarantee that any particular product candidate will be successful and become a commercial product.

Furthermore, our research, testing, pricing, marketing and other operations are subject to extensive regulation by domestic and foreign government regulatory authorities. In addition, sales of our products are affected by reimbursement policies imposed by third party payors, including governments, private insurance plans and managed care providers. These government regulations and reimbursement policies may affect the development, usage and pricing of our products.

In addition, while we routinely obtain patents for our products and technology, the protection offered by our patents and patent applications may be challenged, invalidated or circumvented by our competitors.

Because forward-looking statements involve risks and uncertainties, actual results may differ materially from current results expected by Amgen. Amgen is providing this information as of March 20, 2003, and expressly disclaims any duty to update information contained in this press release.

Contact: Amgen, Thousand Oaks, California, USA

Barbara Bronson Gray (media)

(805) 447-4949

Cary Rosansky (investors)

(805) 447-4634

Note: An electronic version of this news release may be accessed on our web site at www.amgen.com.