<PAGE>
PROSPECTUS SUPPLEMENT DATED DECEMBER 22, 2000 FILED PURSUANT TO RULE 424(b)(3)
TO PROSPECTUS DATED FEBRUARY 9, 2000 REGISTRATION NO. 333-92577
CUSIP NO. 00826TAB4
AFFYMETRIX, INC.
$150,000,000
5% CONVERTIBLE SUBORDINATED NOTES DUE 2006 AND
2,439,024 SHARES OF COMMON STOCK ISSUABLE UPON CONVERSION OF THE NOTES
The information contained herein reflects the two-for-one stock split of the
Company's outstanding shares of common stock effective August 21, 2000.
This prospectus supplement supplements information contained in the
prospectus dated February 9, 2000 relating to the potential sale from time to
time of up to $150,000,000 aggregate amount of notes and the common stock into
which the notes are convertible. This prospectus supplement is not complete
without, and may not be delivered or utilized except in connection with, the
prospectus, including any amendments or supplements to it.
The following table supplements the information set forth in the prospectus
under the caption "Selling Security Holders" with respect to the selling holders
and the respective principal amounts of notes beneficially owned by the selling
holders that may be offered pursuant to the prospectus, as amended or
supplemented:
<TABLE>
<CAPTION>
PRINCIPAL AMOUNT COMMON STOCK
OF NOTES ISSUABLE UPON
BENEFICIALLY OWNED CONVERSION OF COMMON STOCK
NAME AND OFFERED THE NOTES OFFERED
---- ------------------ ------------- ------------
<S> <C> <C> <C>
The Class 1C Company Ltd.......................... 1,500,000 24,390 24,390
McMahan Securities Co. L.P........................ 1,590,000 25,853 25,853
</TABLE>
None of the above selling holders nor any of their affiliates, officers,
directors or principal equity holders has held any position or office or has had
any material relationship with us within the past three years.
