


                                                                      EXHIBIT 24



                               POWER OF ATTORNEY

KNOW ALL MEN BY THESE PRESENTS, that the undersigned, in his or her capacity or
capacities as an officer or director or both of Laboratory Corporation of
America Holdings does hereby constitute and appoint Bradford T. Smith, the true
and lawful attorney and agent of the undersigned, with power of substitution,
to do any and all acts and things for and on behalf of the undersigned and in
the name of the undersigned and in the capacity or capacities of the
undersigned as aforesaid and to execute any and all instruments for and on
behalf of the undersigned and in the name of the undersigned, which said
attorney and agent may deem necessary or advisable to enable said corporation
to comply with the Securities Act of 1933, as amended, and any rules,
regulations, and requirements of the Securities and Exchange Commission, in
connection with this Registration Statement, including specifically but without
limitation, power and authority to sign for the undersigned in the capacities
indicated below, any and all amendments (including post-effective amendments)
hereto; and the undersigned does hereby ratify and confirm all that the said
attorney and agent, or his substitute or substitutes, shall do or cause to be
done by virtue hereof.

         IN WITNESS WHEREOF, the undersigned has executed this power of
attorney this 7th day of January, 2000.



                                               /s/ Thomas P. Mac Mahon
                                               ---------------------------------
                                               THOMAS P. MAC MAHON


                                      19
<PAGE>


                               POWER OF ATTORNEY

KNOW ALL MEN BY THESE PRESENTS, that the undersigned, in his or her capacity or
capacities as an officer or director or both of Laboratory Corporation of
America Holdings does hereby constitute and appoint Bradford T. Smith, the true
and lawful attorney and agent of the undersigned, with power of substitution,
to do any and all acts and things for and on behalf of the undersigned and in
the name of the undersigned and in the capacity or capacities of the
undersigned as aforesaid and to execute any and all instruments for and on
behalf of the undersigned and in the name of the undersigned, which said
attorney and agent may deem necessary or advisable to enable said corporation
to comply with the Securities Act of 1933, as amended, and any rules,
regulations, and requirements of the Securities and Exchange Commission, in
connection with this Registration Statement, including specifically but without
limitation, power and authority to sign for the undersigned in the capacities
indicated below, any and all amendments (including post-effective amendments)
hereto; and the undersigned does hereby ratify and confirm all that the said
attorney and agent, or his substitute or substitutes, shall do or cause to be
done by virtue hereof.

         IN WITNESS WHEREOF, the undersigned has executed this power of
attorney this 7th day of January, 2000.


                                             /s/ Wesley R. Elingburg
                                             -----------------------
                                             WESLEY R. ELINGBURG


                                      20
<PAGE>


                               POWER OF ATTORNEY

KNOW ALL MEN BY THESE PRESENTS, that the undersigned, in his or her capacity or
capacities as an officer or director or both of Laboratory Corporation of
America Holdings does hereby constitute and appoint Bradford T. Smith, the true
and lawful attorney and agent of the undersigned, with power of substitution,
to do any and all acts and things for and on behalf of the undersigned and in
the name of the undersigned and in the capacity or capacities of the
undersigned as aforesaid and to execute any and all instruments for and on
behalf of the undersigned and in the name of the undersigned, which said
attorney and agent may deem necessary or advisable to enable said corporation
to comply with the Securities Act of 1933, as amended, and any rules,
regulations, and requirements of the Securities and Exchange Commission, in
connection with this Registration Statement, including specifically but without
limitation, power and authority to sign for the undersigned in the capacities
indicated below, any and all amendments (including post-effective amendments)
hereto; and the undersigned does hereby ratify and confirm all that the said
attorney and agent, his substitute or substitutes, shall do or cause to be done
by virtue hereof.

         IN WITNESS WHEREOF, the undersigned has executed this power of
attorney this 7th day of January, 2000.



                                             /s/ Jean-Luc Belingard
                                             ----------------------
                                             JEAN-LUC BELINGARD


                                      21

<PAGE>


                               POWER OF ATTORNEY

KNOW ALL MEN BY THESE PRESENTS, that the undersigned, in his or her capacity or
capacities as an officer or director or both of Laboratory Corporation of
America Holdings does hereby constitute and appoint Bradford T. Smith, the true
and lawful attorney and agent of the undersigned, with power of substitution,
to do any and all acts and things for and on behalf of the undersigned and in
the name of the undersigned and in the capacity or capacities of the
undersigned as aforesaid and to execute any and all instruments for and on
behalf of the undersigned and in the name of the undersigned, which said
attorney and agent may deem necessary or advisable to enable said corporation
to comply with the Securities Act of 1933, as amended, and any rules,
regulations, and requirements of the Securities and Exchange Commission, in
connection with this Registration Statement, including specifically but without
limitation, power and authority to sign for the undersigned in the capacities
indicated below, any and all amendments (including post-effective amendments)
hereto; and the undersigned does hereby ratify and confirm all that the said
attorney and agent, or his substitute or substitutes, shall do or cause to be
done by virtue hereof.

         IN WITNESS WHEREOF, the undersigned has executed this power of
attorney this 7th day of January, 2000.



                                             /s/ Wendy E. Lane
                                             -----------------
                                             WENDY E. LANE


                                      22
<PAGE>


                               POWER OF ATTORNEY

KNOW ALL MEN BY THESE PRESENTS, that the undersigned, in his or her capacity or
capacities as an officer or director or both of Laboratory Corporation of
America Holdings does hereby constitute and appoint Bradford T. Smith, the true
and lawful attorney and agent of the undersigned, with power of substitution,
to do any and all acts and things for and on behalf of the undersigned and in
the name of the undersigned and in the capacity or capacities of the
undersigned as aforesaid and to execute any and all instruments for and on
behalf of the undersigned and in the name of the undersigned, which said
attorney and agent may deem necessary or advisable to enable said corporation
to comply with the Securities Act of 1933, as amended, and any rules,
regulations, and requirements of the Securities and Exchange Commission, in
connection with this Registration Statement, including specifically but without
limitation, power and authority to sign for the undersigned in the capacities
indicated below, any and all amendments (including post-effective amendments)
hereto; and the undersigned does hereby ratify and confirm all that the said
attorney and agent, or his substitute or substitutes, shall do or cause to be
done by virtue hereof.

         IN WITNESS WHEREOF, the undersigned has executed this power of
attorney this 7th day of January, 2000.



                                             /s/ Robert E. Mittelstaedt, Jr.
                                             -------------------------------
                                             ROBERT E. MITTELSTAEDT, JR.


                                      23
<PAGE>


                               POWER OF ATTORNEY

KNOW ALL MEN BY THESE PRESENTS, that the undersigned, in his or her capacity or
capacities as an officer or director or both of Laboratory Corporation of
America Holdings does hereby constitute and appoint Bradford T. Smith, the true
and lawful attorney and agent of the undersigned, with power of substitution,
to do any and all acts and things for and on behalf of the undersigned and in
the name of the undersigned and in the capacity or capacities of the
undersigned as aforesaid and to execute any and all instruments for and on
behalf of the undersigned and in the name of the undersigned, which said
attorney and agent may deem necessary or advisable to enable said corporation
to comply with the Securities Act of 1933, as amended, and any rules,
regulations, and requirements of the Securities and Exchange Commission, in
connection with this Registration Statement, including specifically but without
limitation, power and authority to sign for the undersigned in the capacities
indicated below, any and all amendments (including post-effective amendments)
hereto; and the undersigned does hereby ratify and confirm all that the said
attorney and agent, or his substitute or substitutes, shall do or cause to be
done by virtue hereof.

         IN WITNESS WHEREOF, the undersigned has executed this power of
attorney this 7th day of January, 2000.



                                             /s/ James B. Powell, M.D.
                                             -------------------------
                                             JAMES B. POWELL, M.D.


                                      24


<PAGE>


                               POWER OF ATTORNEY

KNOW ALL MEN BY THESE PRESENTS, that the undersigned, in his or her capacity or
capacities as an officer or director or both of Laboratory Corporation of
America Holdings does hereby constitute and appoint Bradford T. Smith, the true
and lawful attorney and agent of the undersigned, with power of substitution,
to do any and all acts and things for and on behalf of the undersigned and in
the name of the undersigned and in the capacity or capacities of the
undersigned as aforesaid and to execute any and all instruments for and on
behalf of the undersigned and in the name of the undersigned, which said
attorney and agent may deem necessary or advisable to enable said corporation
to comply with the Securities Act of 1933, as amended, and any rules,
regulations, and requirements of the Securities and Exchange Commission, in
connection with this Registration Statement, including specifically but without
limitation, power and authority to sign for the undersigned in the capacities
indicated below, any and all amendments (including post-effective amendments)
hereto; and the undersigned does hereby ratify and confirm all that the said
attorney and agent, or their substitute or substitutes, shall do or cause to be
done by virtue hereof.

         IN WITNESS WHEREOF, the undersigned has executed this power of
attorney this 7th day of January, 2000.



                                             /s/ David B. Skinner, M.D.
                                             --------------------------
                                             DAVID B. SKINNER, M.D.


                                      25


<PAGE>


                               POWER OF ATTORNEY

KNOW ALL MEN BY THESE PRESENTS, that the undersigned, in his or her capacity or
capacities as an officer or director or both of Laboratory Corporation of
America Holdings does hereby constitute and appoint Bradford T. Smith, Esq.,
the true and lawful attorney and agent of the undersigned, with power of
substitution, to do any and all acts and things for and on behalf of the
undersigned and in the name of the undersigned and in the capacity or
capacities of the undersigned as aforesaid and to execute any and all
instruments for and on behalf of the undersigned and in the name of the
undersigned, which said attorney and agent, may deem necessary or advisable to
enable said corporation to comply with the Securities Act of 1933, as amended,
and any rules, regulations, and requirements of the Securities and Exchange
Commission, in connection with this Registration Statement, including
specifically but without limitation, power and authority to sign for the
undersigned in the capacities indicated below, any and all amendments
(including post-effective amendments) hereto; and the undersigned does hereby
ratify and confirm all that the said attorney and agent, or his substitute or
substitutes, shall do or cause to be done by virtue hereof.

         IN WITNESS WHEREOF, the undersigned has executed this power of
attorney this 7th day of January, 2000.



                                             /s/ Andrew G. Wallace, M.D.
                                             ---------------------------
                                             ANDREW G. WALLACE, M.D.


                                      26
