This filing is made pursuant to Rule
PROSPECTUS SUPPLEMENT NO. 4 TO          424(b)(3) under the Securities Act of
PROSPECTUS DATED JANUARY 15, 2002       1933 in connection with Registration No.
                                        333-71896


                   LABORATORY CORPORATION OF AMERICA HOLDINGS

                                  $744,000,000
 Aggregate Principal Amount at Maturity of Liquid Yield Option(TM)Notes due 2021
                          (Zero Coupon - Subordinated)
                                      and
         Common Stock issuable upon Conversion or Purchase of the LYONs


     This prospectus supplement will be used by the holders of LYONs listed
below to resell their LYONs or the shares of our common stock, par value $0.10
per share, issuable upon conversion or purchase of the LYONs.

     You should read this prospectus supplement together with the prospectus
dated January 15, 2002, which is to be delivered with this prospectus
supplement.

     The table below sets forth additional and updated information concerning
beneficial ownership of the LYONs, and supplements and, to the extent
inconsistent with, amends the table appearing under the caption "Selling
Securityholders" beginning on page 37 of the prospectus. To the extent that a
selling securityholder is listed both in the table below and in the table
appearing in the prospectus, the information set forth below regarding that
selling securityholder supersedes the information set forth in the prospectus.
In addition, the information set forth below regarding all other holders of
LYONs or future transferees, pledgees, donees, assignees or successors of any
holders supersedes the information regarding such other holders appearing on
page 41 of the prospectus. We have prepared this table based on information
given to us by the selling securityholders listed below prior to the date
hereof.


                                                     Aggregate       Percentage of      Number of      Percentage of
                                                  Principal Amount       LYONs          Shares of      Common Stock
                                                   at Maturity of     Outstanding      Common Stock    Outstanding
                                                  LYONs Owned and     Prior to the    Owned and that   Prior to the
Name                                              that May be Sold      Offering     May be Sold (1)   Offering (2)
-----------------------------------------------   ----------------   -------------   ---------------   ------------
                                                                                                 
Argent Classic Convertible Arbitrage Fund
(Bermuda) Ltd.                                      $ 10,000,000        1.34%              67,054            *
Argent LowLev Convertible Arbitrage Fund LLC           1,000,000         *                  6,705            *
Argent LowLev Convertible Arbitrage Fund Ltd.         18,500,000        2.49%             124,049            *
Lyxor Master Fund Ref: Argent/LowLev CB                1,000,000         *                  6,705            *
Merrill Lynch, Pierce, Fenner and Smith, Inc
(6)                                                    1,845,000         *                 12,371            *
TD Securities (USA) Inc.                              50,000,000        6.72%             335,270            *
Zurich Institutional Benchmark Master Fund
Ltd.                                                   1,000,000         *                  6,705            *
All Other Holders of LYONs or Future
Transferees, Pledgees, Donees, Assignees or
Successors of any Holders (3) (4)                     41,425,000        5.57%             277,771            *
-------------------------------------------------------------------------------------------------------------------
Total (5)                                           $744,000,000         100%           4,988,817           7.05%


---------
* Less than 1%.





(1)  Assumes conversion of all of the holder's LYONs at a conversion rate of
     6.7054 shares of common stock per $1,000 principal amount at maturity of
     the LYONs. This conversion rate is subject to adjustment, however, as
     described





     under "Description of LYONs--Conversion Rights--Conversion Adjustments and
     Delivery of Common Stock" beginning on page 16 of the prospectus. As a
     result, the number of shares of common stock issuable upon conversion of
     the LYONs may increase or decrease in the future.

(2)  Calculated based on Rule 13d-3(d)(1)(i) of the Exchange Act using
     70,764,165 shares of common stock outstanding as of February 1, 2002. In
     calculating this amount for each holder, we treated as outstanding the
     number of shares of common stock issuable upon conversion of all of that
     holder's LYONs, but we did not assume conversion of any other holder's
     LYONs.

(3)  Information about other selling securityholders will be set forth in
     future prospectus supplements, as required.

(4)  Assumes that any other holders of LYONs, or any future pledgees, donees,
     assignees, transferees or successors of or from any other holders of
     LYONs, do not beneficially own any shares of common stock other than the
     shares of common stock issuable upon conversion of the LYONs at the
     initial conversion rate.

(5)  Total number of shares of common stock that may be sold and the related
     percentage of common stock outstanding assumes the conversion in full of
     all LYONs outstanding. However, as described under "Description of
     LYONs--Conversion Rights" beginning on page 14 of the prospectus, a holder
     of a LYON otherwise entitled to a fractional share of our common stock
     will receive cash equal to the then current sale price of the fractional
     share.

(6)  Merrill Lynch, Pierce Fenner and Smith, Inc. was the initial purchaser in
     connection with the private placement of the LYONs and, along with certain
     of its affiliates, has engaged and may engage in investment banking
     transactions with us and has from time to time acted as a financial
     advisor to us.

                                   ---------

     Investing in the LYONs involves risks that are described in "Risk Factors
Relating to the LYONs" beginning on page 8 of the prospectus.

     Neither the Securities and Exchange Commission nor any state securities
commission has approved or disapproved 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 February 8, 2002


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