
<PAGE>

                                                                     EXHIBIT 5.1

                               Alston & Bird LLP

                              One Atlantic Center
                          1201 West Peachtree Street
                          Atlanta, Georgia 30309-3424

                                 404-881-7000
                               Fax: 404-881-7777
                                www.alston.com

                                April 20, 2001


     AmeriPath, Inc.
     7289 Garden Road
     Suite 200
     Riviera Beach, Florida  33404

          Re:  Form S-3 Registration Statement -
               Resale of Stock on Behalf of Certain Selling Stockholders

     Ladies and Gentlemen:

          We have acted as counsel to AmeriPath, Inc., a Delaware corporation
     (the "Company"), in connection with the above-referenced Registration
     Statement on Form S-3 (the "Registration Statement") being filed by the
     Company with the Securities and Exchange Commission (the "Commission")
     under the Securities Act of 1933, as amended, and covering 864,849 shares
     (the "Shares") of the Company's common stock, $.01 par value ("Common
     Stock"), which are being offered for the account of certain selling
     stockholders specified therein. The opinion hereinafter set forth is given
     at the request of the Company pursuant to Item 16 of Form S-3 and Item
     601(b)(5) of Regulation S-K.

          In the capacity described above, we have considered such matters of
     law and of fact, including the examination of originals or copies,
     certified or otherwise identified to our satisfaction, of such records and
     documents of the Company, certificates of officers of the Company,
     certificates of public officials and such other documents as we have deemed
     appropriate as a basis for the opinion hereinafter set forth.

          As to certain factual matters relevant to this opinion letter, we have
     relied upon the representations and warranties of the parties to the
     Agreement and Plan of Merger included as Exhibit 2.1 to the Registration
     Statement, certificates and statements of officers of the Company and
     certificates of public officials. Except to the extent expressly set forth
     herein, we have made no independent investigations with regard thereto,
     and, accordingly, we do not express any opinion as to matters that might
     have been disclosed by independent verification.

          The opinion set forth herein is limited to the General Corporation Law
     of the State of Delaware. The only opinion rendered by us consists of those
     matters set forth in the

<TABLE>
<S>                                        <C>                       <C>                            <C>
       Bank of America Plaza                 90 Park Avenue           3605 Glenwood Avenue          601 Pennsylvania Avenue, N.W.
101 South Tryon Street, Suite 4000         New York, NY 10016               Suite 310                 North Building, 11th Floor
    Charlotte, NC 28280-4000                  212-210-9400           Raleigh, NC 27612-4957            Washington, DC 20004-2601
          704-444-1000                     Fax: 212-210-9444             919-420-2200                        202-756-3300
       Fax: 704-444-1111                                              Fax: 919-420-2260                    Fax: 202-756-3333
</TABLE>
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     AmeriPath, Inc.
     April 20, 2001
     Page 2

     immediately following paragraph, and no opinion may be implied or inferred
     beyond the opinion expressly stated.

          Based upon the foregoing it is our opinion that (i) the currently
     outstanding Shares are legally and validly issued, fully paid and
     nonassessable and (ii) the Shares issuable pursuant to currently
     outstanding warrants, when issued and delivered against payment therefor in
     accordance with the terms of such warrants, will be legally and validly
     issued, fully paid and nonassessable.

          This opinion letter is provided solely with regard to the Registration
     Statement, may be relied upon only in connection with the Registration
     Statement, and may not be relied upon for any other purpose without our
     prior written consent.

          We hereby consent to the filing of this opinion as an exhibit to the
     Registration Statement and further consent to the use of our name under the
     heading "Legal Matters" in the Prospectus constituting a part thereof. In
     giving such consent, we do not thereby admit that we are within the
     category of persons whose consent is required under Section 7 of the
     Securities Act of 1933, as amended, or the rules and regulations of the
     Commission thereunder.

                                   Sincerely,

                                   ALSTON & BIRD LLP


                                   By:  /s/ Nils H. Okeson
                                      -----------------------------
                                       Nils H. Okeson,
                                       a partner


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ATL01/10957010v1
