Affymetrix Announces Management Changes

Affymetrix Inc. (Nasdaq:AFFX) announced today that
President and Director, Susan E. Siegel, is transitioning from her
current role and will continue with the company as President Emeritus,
serving as an advisor and reporting to Stephen P.A. Fodor, Ph.D.,
founder, chairman and CEO. Effective immediately, Thane Kreiner,
Ph.D., has been named Senior Vice President of Marketing and Sales,
reporting to the CEO.
   "Sue has been very instrumental in building the commercial
organization and the company," said Dr. Fodor. "She has been key to
Affymetrix' evolution from a small company to a more than $350 million
global enterprise. We look forward to Sue's continued involvement in
an advisory role."
   Siegel joined Affymetrix in 1998 as Senior Vice President of Sales
and Marketing and oversaw the successful build up of Affymetrix'
global commercial infrastructure. In 1999, Siegel was promoted to
President and in 2001, she became a board member.
   After joining Affymetrix in 1993, Dr. Kreiner has held numerous
roles in the company, including heading sales and marketing and
project management. "Thane has been a key player in developing many
new market opportunities for Affymetrix. His excellent life-science
domain knowledge and understanding of our technology and customers
make him uniquely qualified to lead this important function," said Dr.
Fodor.
   In addition, Richard P. Rava, Ph.D., the scientific co-founder of
Affymetrix, has been appointed to head Product Development. "Rich has
been a pioneer in the design and development of microarray
technologies for more than twelve years at Affymetrix. His experience
and technical leadership will provide the necessary skills to deliver
advanced scientific products to the market place," said Dr. Fodor.

   About Affymetrix

   Affymetrix scientists invented the world's first microarray in
1989 and began selling the first commercial microarray in 1994. Since
then, Affymetrix GeneChip(R) technology has become the industry
standard in molecular biology research. Affymetrix technology is used
by the world's top pharmaceutical, diagnostic and biotechnology
companies, as well as by leading academic, government and
not-for-profit research institutes. More than 1,400 GeneChip systems
have been shipped around the world and more than 4,000 peer-reviewed
papers have been published using the technology. Affymetrix' patented
photolithographic manufacturing process provides the highest
information capacity available today on an array, enabling researchers
to use a whole-genome approach to analyze the relationship between
genetics and health. Affymetrix is headquartered in Santa Clara,
Calif., with manufacturing facilities in Sacramento, Calif., and
Bedford, Mass. The company maintains important sales and marketing
operations in Europe and Asia and has about 1,000 employees worldwide.
For more information about Affymetrix, please visit the company's Web
site at www.affymetrix.com.

   NOTE: Affymetrix, the Affymetrix logo and GeneChip are registered
trademarks owned or used by Affymetrix Inc.