<PAGE>
Filed pursuant to Rule 424(b)(3)
Registration No. 333-78909
Prospectus Supplement
(To Prospectus Dated June 11, 1999)
$850,000,000
[LOGO OF CITRIX]
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 of Debentures Percentage of Number of
Beneficially Owned That May Debentures Conversion Shares
Name Be Sold Outstanding That May Be Sold
---- --------------------------- ------------- -----------------
<S> <C> <C> <C>
Conseco Senior Health Insurance Company - Convertible 750,000 0.088% 5,272
Conseco Health Insurance Company - Convertible 750,000 0.088% 5,272
Conseco Variable Insurance Company - Convertible 750,000 0.088% 5,272
Conseco Fund Group - Convertible Securities Fund 750,000 0.088% 5,272
Any other holder of Debentures or future $9,807,000 1.15% 68,998
transferee from any such holder
</TABLE>
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The Date Of This Prospectus Supplement Is January 21, 2000.
