AFFYMETRIX CLOSES $ 275 MILLION SENIOR CONVERTIBLE NOTES OFFERING

Exhibit 99.3

FOR IMMEDIATE RELEASE

Contact: Affymetrix, Inc.

Doug Farrell, 408-731-5285

Vice President of Investor Relations

AFFYMETRIX CLOSES $ 275 MILLION SENIOR CONVERTIBLE NOTES OFFERING

Santa Clara, Calif. — November 16 , 2007 — Affymetrix, Inc., (Nasdaq: AFFX) today announced the closing of its previously announced registered offering of $275 million aggregate principal amount of unsecured 3.50% Senior Convertible Notes due 2038.

As previously announced, the Company intends to use the net proceeds from the offering for working capital and general corporate purposes, which may include funding its operations, capital expenditures, potential acquisitions of businesses, product or technologies it believes to be of strategic importance and repurchases or redemption of all or a portion of its 0.75% Senior Convertible Notes due 2033.

The notes will be convertible into Affymetrix common stock at an initial conversion rate of 33.191 shares per $1,000 principal amoun