<PAGE>
Filed Pursuant to Rule 424(b)(3)
Registration No. 333-78909
Prospectus Supplement
(To Prospectus Dated June 11, 1999)
$850,000,000
[CITRIX logo]
Zero Coupon Convertible Subordinated Debentures Due 2019
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This prospectus supplement relates to the resale by the holders of
Citrix Systems, Inc. Zero Coupon Convertible Subordinated Debentures Due 2019
and the shares of common stock, $.001 par value per share, issuable upon the
conversion of the debentures.
This prospectus supplement should be read in conjunction with, and may
not be delivered or utilized without, the prospectus dated June 11, 1999,
including any amendments or supplements thereto. The terms of the debentures
are set forth in the prospectus.
The information in the table appearing under the heading "Selling
Securityholders" in the prospectus is amended by adding the information below
with respect to persons not previously listed in the prospectus or in any
amendments or supplements thereto, and by superceding the information with
respect to persons previously listed in the prospectus or in any amendments or
supplements thereto that are listed below:
<TABLE>
<CAPTION>
Principal Amount at Maturity Number of
of Debentures Beneficially Percentage of Conversion Shares
Name Owned That May Be Sold Debentures Outstanding That May Be Sold
---- ---------------------- ---------------------- ----------------
<S> <C> <C> <C>
SG Cowen Securities Corp. $ 5,000,000 0.59% 35,153
Any other holder of
Debentures or future
transferee from any
such holder $81,368,000 9.57% 572,104
</TABLE>
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The Date Of This Prospectus Supplement Is October 14, 1999.
