Filed pursuant to Rule 424(b)(3)
                                                          File Number 333-51548

PROSPECTUS SUPPLEMENT NO. 18

                                $4,657,500,000

                            Tyco International Ltd.

                    Liquid Yield Option(TM) Notes Due 2020
                             (Zero Coupon--Senior)
                                      and
                          Common Shares Issuable Upon
                    Conversion and/or Purchase of the LYONs

   This prospectus supplement supplements the prospectus dated December 18,
2000 of Tyco International Ltd., as supplemented December 21, 2000, January 5,
2001, January 12, 2001, January 25, 2001, February 9, 2001, February 26, 2001,
March 9, 2001, March 30, 2001, April 20, 2001, June 4, 2001, June 26, 2001,
July 13, 2001, August 10, 2001, September 4, 2001, October 5, 2001, November 6,
2001, and December 26, 2001, relating to the sale by certain of our
securityholders (including their pledgees, donees, assignees, transferees,
successors and others who later hold any of our securityholders' interests) of
up to $4,657,500,000 aggregate principal amount at maturity of LYONs and the
common shares issuable upon conversion, and/or purchase by us, of the LYONs.
You should read this prospectus supplement in conjunction with the prospectus,
and this prospectus supplement is qualified by reference to the prospectus,
except to the extent that the information in this prospectus supplement
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.

   The table in the "Selling Securityholders" section on page 34 of the
prospectus is hereby further supplemented by the addition of the following
information regarding selling securityholders, which information includes
amounts that are in addition to, and that, in some cases, may be in
substitution for, amounts listed for the same or other selling securityholders
in the prospectus and in prior supplements.



                                                 Aggregate Principal               Number of
                                                      Amount at      Percentage  Common Shares Percentage of
                                                  Maturity of LYONs   of LYONs    That May be  Common Shares
Name                                              That May be Sold   Outstanding    Sold(1)    Outstanding(2)
- ----                                             ------------------- ----------- ------------- --------------
                                                                                   
Goldman Sachs and Company.......................    $133,772,000         2.9%      1,378,038         *
Merrill Lynch, Pierce, Fenner and Smith, Inc.(3)     188,450,000         4.0       1,941,298         *

- --------
 *  Less than one percent (1%).
(1) Assumes conversion of all of the holder's LYONs at a conversion rate of
    10.3014 common shares per $1,000 principal amount at maturity of the LYONs.
    This conversion rate is subject to adjustment, however, as described under
    "Description of the LYONs--Conversion Rights--Conversion Rate and Delivery
    of Common Shares." As a result, the number of common shares issuable upon
    conversion of the LYONs may increase or decrease in the future. Does not
    include common shares that may be issued by us upon purchase of LYONs by us
    at the option of the holder.
(2) Calculated based on Rule 13d-3(d)(i) of the Exchange Act, using
    1,996,358,786 Tyco common shares outstanding as of February 13, 2002. In
    calculating this amount for each holder, we treated as outstanding the
    number of common shares issuable upon conversion of all of that holder's
    LYONs, but we did not assume conversion of any other holder's LYONs. Does
    not include common shares that may be issued by us upon purchase of LYONs
    by us at the option of the holder.
(3) Merrill Lynch, Pierce, Fenner & Smith Incorporated and Tyco International
    Ltd. and its affiliates have, within the past three years, engaged in, and
    may in the future engage in, investment banking and other commercial
    dealings, and Merrill Lynch acted as the initial purchaser in the private
    placement in which the LYONs were originally issued. Merrill Lynch has
    received customary fees and commissions for these transactions.

    INVESTING IN THE LYONS INVOLVES RISKS THAT ARE DESCRIBED IN THE "RISK
FACTORS RELATING TO THE LYONS" SECTION BEGINNING ON PAGE 12 OF THE PROSPECTUS.


   Neither the Securities and Exchange Commission, any state securities
commission nor any other regulatory body has approved or disapproved of these
securities or determined if this prospectus is truthful or complete. Any
representation to the contrary is a criminal offense.

           The date of this prospectus supplement is March 22, 2001.

(TM)Trademark of Merrill Lynch & Co., Inc.