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                                                                    EXHIBIT 3.21

[SEAL]

                          ARTICLES OF INCORPORATION OF

                      AMERIPATH LUBBOCK 5.01(a) CORPORATION

     I, the undersigned, natural person of eighteen (18) years or more, acting
as incorporator of a corporation under the Texas Non-Profit Corporation Act, do
hereby adopt the following Articles of Incorporation for such corporation:

                                   ARTICLE ONE

     The name of the corporation is AmeriPath Lubbock 5.0l(a) Corporation.

                                   ARTICLE TWO

     The corporation is a non-profit corporation.

                                 ARTICLE THREE

     The period of its duration is perpetual.

                                  ARTICLE FOUR

          The corporation is organized and shall be operated exclusively to
carry out one or more of the following purposes:

          (a)  conducting scientific research and research projects in the
               public interest in the fields of medical sciences, medical
               economics, public health, sociology and related areas,

          (b)  supporting medical education in medical schools through grants
               and scholarships;

          (c)  improving and developing of the capabilities of individuals and
               institutions studying, teaching and practicing medicine and the
               institutions they serve;

          (d)  delivering health care to the public;

          (e)  engaging in the instruction of the general public in the area of
               medical science, public health and hygiene and related
               instruction useful to the individual and to the community; and

          (f)  conducting other activities useful or appropriate to the
               accomplishment of the foregoing purposes.

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                                  ARTICLE FIVE

          The name and street address of the registered agent and office of the
corporation is Corporation Service Company d/b/a CSC-Lawyers Incorporating
Service Company at 300 Brazos, Austin, Texas 78701.

                                  ARTICLE SIX

          Except as otherwise provided in These Articles of Incorporation and)
in the Bylaws of the corporation, the direction and management of the affairs of
the corporation and the control and disposition of us assets shall be vested in
a. board of directors (the "Board of Directors") composed of such number of
persons (nor less than Time (3)) as may be fixed by the Bylaws of The
corporation. The authority of the Board of Directors shall be limited to the
extent expressly set forth in these Articles of Incorporation and in the Bylaws
of the corporation. The number of directors presently constituting the Board of
Directors is three (3), The names and addresses of the persons who shall serve
as the initial directors of the corporation are as follows.

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<Caption>
              NAME                                                     ADDRESS
              ----                                                     -------
                                                          
     Clay J. Cockerell, M.D.                                 2330 Butler Street, Suite 115
                                                             Dallas, Texas 75235

     Joseph A Sorrier, M.D.                                  4350 Alpha Rd
                                                             Dallas, Texas 75244

     Stephen Aldred, M.D.                                    5522 Wenonah Drive
                                                             Dallas, Texas 75209
</Table>

     Each director shall hold office for the term for which he or she is
elected, except that the initial directors of the corporation named in those
Articles of Incorporation shall hold office for the terms specified in the
Bylaws of the corporation to be held by such directors, and until his or her
successor shall have been duly elected and qualified unless such director is
sooner removed in the manner provided in the Bylaws of the corporation or he or
she resigns or dies.

          Each director and successor director shall at all times be a physician
duly licensed to practice medicine by the Texas State Board of Medical Examiners
and actively engaged in The practice of medicine for purposes of these Articles
of Incorporation, the term "actively engaged in the practice of medicine" shaft
be as defined by the Texas State Board of Medical Examiners.

                                 ARTICLE SEVEN

          The corporation shall have one member. These Articles of Incorporation
and the Bylaws of the corporation shall define the voting rights, powers and
privileges of the member.

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                                  ARTICLE EIGHT

          The initial Bylaws of the corporation shall be adopted by the Board of
Directors. The Articles of Incorporation and the Bylaws may be altered, amended
or repealed and new and other Bylaws may be made and adopted only by the member,
provided that any alteration, amendment or repeal, of the Bylaws, must be
approved by a majority of the Board of Directors then in office.

                                  ARTICLE NINE

          The power to dissolve the corporation in accordance with the Texas
NonProfit Corporation Act shall be vested solely in the member.

                                  ARTICLE TEN

          Any action required to, or which may, be taken at a meeting of the
member or directors of the corporation or a committee of the board of directors
may be taken without a meeting if a consent in writing, setting forth the action
to be taken, is signed by the member, or a sufficient number of directors or
committee members as would be necessary to take that action at a meeting at
which the member or all of the directors or committee members were present and
voted, provided such consent is in the form provided for and such action is
taken in accordance with the Act, these Articles of Incorporation and the Bylaws
of the corporation.

                                 ARTICLE ELEVEN

          Pursuant to Article 6.02, Subsection (3) of the Texas Non-Profit
Corporation Act, upon dissolution of the corporation in accordance with the laws
of the State of Texas, the Board of Directors, after paying or making provision
for payment of all liabilities of the corporation, and after returning,
transferring, or conveying those assets of the corporation that are held subject
to conditions requiring such return, transfer, or conveyance, shall distribute
all the corporation's remaining assets as the Board of Directors in its sole
discretion shall determine.

                                 ARTICLE TWELVE

          A director member or committee member of the corporation shall not be
liable to the corporation for monetary damages for an act or omission in the
director's capacity as a director, except that this Article Twelve does not
eliminate or limit the liability of a director of the corporation to the extent
the director is found liable for, (i) a breach of the director's duty of loyalty
to the Corporation or its members; (ii) an act or omission not in good faith
that constitutes a breach of duty of the director to the corporation or an act
or omission that involves intentional misconduct or a knowing violation of the
law; (iii) a transaction from which the director received an improper benefit,
whether or not the benefit resulted from an action taken within The scope of the
director's office, or (iv) an act or omission for which the liability of a
director is expressly provided by an applicable statute. If the Texas
Miscellaneous Corporation Laws Act or any other statute of the State of Texas
hereafter is amended to authorize the further elimination or limitation of the
liability of directors of the corporation, then the liability of a director of
the corporation shall be limited to the fullest extent permitted by the statutes
of the State of Texas, as so amended, and such elimination or limitation of

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liability shall be in addition to, and not in lieu of, the limitation on the
liability of a director of the corporation provided by the foregoing provisions
of this Article Twelve. Any repeal of or amendment to this Article Twelve shall
be prospective only and shall not adversely affect any limitation on the
liability of a director of the corporation existing at the time of such repeal
or amendment.

                                ARTICLE THIRTEEN

          The name and business address of the incorporator is:

<Table>
<Caption>
                    NAME                                                ADDRESS
                    ----                                                -------
                                                          
          Clay J. Cockerell, M.D.                            2330 Butler Street, Suite 115
                                                             Dallas, Texas 75235
</Table>

          IN WITNESS WHEREOF, I have hereunto set my hand on this 9th day of
June, 1998


                                                   By: /s/ Clay J. Cockerell
                                                      --------------------------
                                                        Clay J. Cockerell, M.D
                                                        Incorporator

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