Exhibit 99.1

                            Tyco International Ltd.
                              The Gibbons Building
                           10 Queen Street, Suite 301
                             Hamilton HM11, Bermuda


FOR IMMEDIATE RELEASE                    CONTACT:
                                         J. Brad McGee
                                         Tyco International (US) Inc.
                                         Senior Vice President
                                         (603) 778-9700


         Hamilton,   Bermuda,   December  9,  1999  -  Tyco  International  Ltd.
(NYSE-TYC,  LSE-TYI,  BSX-TYC) said today that it was advised yesterday that the
staff of the U.S. Securities and Exchange Commission is conducting a "nonpublic,
informal  inquiry" relating to charges and reserves taken in connection with the
company's  acquisitions.  Pursuant  to this  inquiry,  Tyco  will  be  providing
information and documents to the staff on a voluntary basis.

         "In light of the recent  market  activity  in our  stock,  which is not
justified by any  development  at the  company,  we welcome the  opportunity  to
respond to this request. We remain confident of our accounting methodology,  our
public disclosures and the continuing  strength of our business," said L. Dennis
Kozlowski, Chairman and CEO of Tyco.

         The company's  Annual Report on Form 10-K for the 1999 fiscal year will
be filed on December 13, 1999 as scheduled.

         Tyco  International  Ltd.,  a  diversified  manufacturing  and  service
company,  is the world's  largest  manufacturer  and servicer of electrical  and
electronic  components  and  undersea  telecommunications  systems,  the world's
largest  manufacturer,  installer,  and provider of fire protection  systems and
electronic  security  services,  has strong  leadership  positions in disposable
medical products,  plastics,  and adhesives,  and is the largest manufacturer of
flow control valves.  The Company  operates in more than 80 countries around the
world and has expected fiscal 2000 revenues in excess of $25 billion.

FORWARD LOOKING INFORMATION

         Comments in this  release  concerning  expected  fiscal 2000 and Tyco's
expectations for continuing  business strength are  forward-looking  statements,
which are based on management's  good faith  expectations and belief  concerning
future   developments.   Actual  results  may   materially   differ  from  these
expectations  as a result of many  factors,  relevant  examples of which are set
forth in the  "Management  Discussion  and Analysis"  section of the Tyco's 1998
Annual Report to  Shareholders,  Tyco's 1998 Annual Report on Form 10-K,  Tyco's
Current Report on Form 8-K filed on June 3, 1999.

# # #
120999 518