EXHIBIT 5.1
                                                                     -----------

                                KIRKLAND & ELLIS
                PARTNERSHIPS INCLUDING PROFESSIONAL CORPORATIONS

                             200 East Randolph Drive
                             Chicago, Illinois 60601

                                 (312) 861-2000                     Facsimile:
                                                                  (312) 861-2200

                                 April 26, 2002

Advantage Payroll Services, Inc.
126 Merrow Road
Auburn, Maine 04211

Ladies and Gentlemen:

     We are acting as special counsel to Advantage Payroll Services, Inc., a
Delaware corporation (the "Company"), in connection with the proposed
registration by the Company of 6,612,500 shares of its Common Stock, par value
$.01 per share (the "Common Stock"), including 862,500 shares of its Common
Stock to cover over-allotments, if any, pursuant to a Registration Statement on
Form S-1, originally filed with the Securities and Exchange Commission (the
"Commission") on March 18, 2002 under the Securities Act of 1933, as amended
(the "Act") (such Registration Statement, as amended or supplemented, is
hereinafter referred to as the "Registration Statement"). Of the shares of
Common Stock to be registered pursuant to the Registration Statement, up to
4,539,473 shares are being offered by the Company (the "Primary Shares") and up
to 2,073,027 shares are being offered by selling stockholders (the "Secondary
Shares").

     In that connection, we have examined originals, or copies certified or
otherwise identified to our satisfaction, of such documents, corporate records
and other instruments as we have deemed necessary for the purposes of this
opinion, including (i) the corporate and organizational documents of the
Company, including the Restated Certificate of Incorporation of the Company (the
"Restated Certificate") to be filed with the Secretary of State of the State of
Delaware prior to the sale of the Primary Shares and the Secondary Shares and
(ii) minutes and records of the corporate proceedings of the Company with
respect to the issuance and sale of the Primary Shares and the original issuance
of the Secondary Shares.



London            Los Angeles            New York               Washington, D.C.



                                KIRKLAND & ELLIS

Advantage Payroll Services, Inc.
April 26, 2002
Page 2


         For purposes of this opinion, we have assumed the authenticity of all
documents submitted to us as originals, the conformity to the originals of all
documents submitted to us as copies and the authenticity of the originals of all
documents submitted to us as copies. We have also assumed the legal capacity of
all natural persons, the genuineness of the signatures of persons signing all
documents in connection with which this opinion is rendered, the authority of
such persons signing on behalf of the parties thereto other than the Company and
the due authorization, execution and delivery of all documents by the parties
thereto other than the Company. We have not independently established or
verified any facts relevant to the opinions expressed herein, but have relied
upon statements and representations of officers and other representatives of the
Company and others.

         Based upon and subject to the foregoing qualifications, assumptions and
limitations and the further limitations set forth below, we are of the opinion
that:

              (1) Upon filing of the Restated Certificate with the Secretary of
         State of the State of Delaware, the Primary Shares will be duly
         authorized, and, when the Registration Statement becomes effective
         under the Act, when the Board of Directors of the Company has taken
         all necessary action to approve the issuance and sale of the Primary
         Shares and when appropriate certificates representing the Primary
         Shares are duly countersigned and registered by the Company's transfer
         agent/registrar and delivered to the Company's underwriters against
         payment of the agreed consideration therefor in accordance with the
         Underwriting Agreement, the Primary Shares will be validly issued,
         fully paid and nonassessable.

              (2) The Secondary Shares have been duly authorized, validly
         issued and fully paid and are nonassessable.

         Our opinions expressed above are subject to the qualifications that we
express no opinion as to the applicability of, compliance with, or effect of any
laws except the General Corporation Law of the State of Delaware.

         We hereby consent to the filing of this opinion with the Commission as
Exhibit 5.1 to the Registration Statement. We also consent to the reference to
our firm under the heading "Legal Matters" in the Registration Statement. In
giving this consent, we do not thereby admit that we are in the category of
persons whose consent is required under Section 7 of the Act or the rules and
regulations of the Commission. This opinion and consent may be incorporated by
reference in a subsequent registration statement on Form S-1 filed pursuant to
Rule 462(b) under the Act with respect to the registration of additional
securities for sale in the offering contemplated by the Registration Statement
and shall cover such additional securities, if any, registered on such
subsequent registration statement.



                                KIRKLAND & ELLIS

Advantage Payroll Services, Inc.
April 26, 2002
Page 3

         We do not find it necessary for the purposes of this opinion, and
accordingly we do not purport to cover herein, the application of the securities
or "Blue Sky" laws of the various states to the issuance and sale of the Primary
Shares and the sale of the Secondary Shares.

         This opinion is limited to the specific issues addressed herein, and no
opinion may be inferred or implied beyond that expressly stated herein. We
assume no obligation to revise or supplement this opinion should the General
Corporation Law of the State of Delaware be changed by legislative action,
judicial decision or otherwise.

         This opinion is furnished to you in connection with the filing of the
Registration Statement, and is not to be used, circulated, quoted or otherwise
relied upon for any other purposes.

                                                     Sincerely,

                                                     /s/ Kirkland & Ellis

                                                     KIRKLAND & ELLIS