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                   PROSPECTUS SUPPLEMENT DATED OCTOBER 2, 1998
                        (TO PROSPECTUS DATED MAY 6, 1998)
  

                                               Filed Pursuant to
                                              Rule 424(b)(3) and (c)
                                           Commission File No. 333-51487
                                               



                                  12,194 Shares

                                  Common Stock

         This Prospectus Supplement supplements the Prospectus dated May 6, 1998
(the "Prospectus") of Cisco Systems, Inc. ("Cisco" or the "Company") relating to
the public offering, which is not being underwritten, and sale by certain
shareholders of the Company or by pledgees, donees, transferees or other
successors in interest that receive such shares as a gift, partnership
distribution or other non-sale related transfer (the "Selling Shareholders") of
up to 12,194 shares of Cisco's Common Stock, par value $0.001 per share (the
"Common Stock"), who received such shares in connection with the acquisition by
statutory merger of NetSpeed, Inc. ("NetSpeed"), by and through a merger of
NetSpeed with and into the Company. This Prospectus Supplement should be read in
conjunction with the Prospectus, and this Prospectus Supplement is qualified by
reference to the Prospectus except to the extent that information herein
contained supersedes the information contained in the Prospectus. Capitalized
terms used in this Prospectus Supplement and not otherwise defined herein have
the meanings specified in the Prospectus.

                              SELLING SHAREHOLDERS

         Recently James M. Mansour transferred 10,765 shares of Common Stock to
Rover Investments Partnership LTD., which entity was not specifically named in
the Prospectus. The following table provides certain information with respect to
the number of shares of Common Stock beneficially owned by a shareholder of the
Company who was not specifically identified in the Prospectus as a Selling
Shareholder, the percentage of outstanding shares of Common Stock of the Company
this represents and the number of shares of Common Stock to be registered for
sale hereby. The table of Selling Shareholders in the Prospectus is hereby
amended to include Rover Investments Partnership LTD. as a Selling Shareholder
and to amend the information provided in the Prospectus with respect to James M.
Mansour to reflect the transfer of 10,765 shares.


                                                                                                      
                                                           Number of                                   Number of  
                                                             Shares            Percent of                Shares
                                                          Beneficially        Outstanding             Registered for   
                                                            Owned(1)             Shares               Sale Hereby(1)
Name of Selling Shareholder                                 --------             -------              --------------
- ---------------------------                                 
                                                                                                
James M. Mansour                                              1,429                  *                    1,429

Rover Investments Partnership LTD                            10,765                  *                   10,765



- ---------------------------

* Represents beneficial ownership of less than 1%.

(1)      The registration statement to which the Prospectus and this Prospectus
         Supplement relate shall also cover any additional shares of Common
         Stock which become issuable in connection with the Shares registered
         for sale hereby by reason of any stock dividend, stock split,
         recapitalization or other similar transaction effected without the
         receipt of consideration which results in an increase in the number of
         the Company's outstanding shares of Common Stock.