<PAGE>   1

================================================================================
     As filed with the Securities and Exchange Commission on March 19, 2001

                                                    Registration No. 333-_______


                                  UNITED STATES
                       SECURITIES AND EXCHANGE COMMISSION

                             WASHINGTON, D.C. 20549

                                ---------------

                                    FORM S-8

             REGISTRATION STATEMENT UNDER THE SECURITIES ACT OF 1933

                                ---------------

                            FIRST HEALTH GROUP CORP.

             (Exact name of Registrant as specified in its charter)

             DELAWARE                                           36-3307583
  (State or other jurisdiction                                (I.R.S. Employer
of incorporation or organization)                            Identification No.)


                              3200 HIGHLAND AVENUE
                          DOWNERS GROVE, ILLINOIS 60515
                                 (630) 737-7900

    (Address, including zip code, and telephone number, including area code,
                       of Registrant's executive offices)

                                ---------------

                 FIRST HEALTH GROUP CORP. 2000 STOCK OPTION PLAN

                            (Full title of the plan)


                            WILLIAM M. HOLZMAN, ESQ.
                            NEAL, GERBER & EISENBERG
                            TWO NORTH LASALLE STREET
                             CHICAGO, ILLINOIS 60602
                                 (312) 269-8000

            (Name, address, including zip code, and telephone number,
                   including area code, of agent for service)

                                ---------------


                        CALCULATION OF REGISTRATION FEE
--------------------------------------------------------------------------------
       TITLE OF SECURITIES             PROPOSED MAXIMUM              AMOUNT OF
        TO BE REGISTERED           AGGREGATE OFFERING PRICE         REGISTRATION
--------------------------------------------------------------------------------
          Common Stock,                 $ 39,812,500 (1)             $9,954.00
         $0.01 par value
--------------------------------------------------------------------------------
(1)   Estimated solely for the purpose of calculating the registration fee
      pursuant to Rules 457(c) and 457(h) under the Securities Act of 1933, as
      amended, on the basis of the average of the high and low prices of the
      Corporation's Common Stock as reported on the Nasdaq National Market
      System on March 15, 2001.



<PAGE>   2
                                     PART II

               INFORMATION REQUIRED IN THE REGISTRATION STATEMENT

ITEM 3.  INCORPORATION OF DOCUMENTS BY REFERENCE

      The following documents are incorporated into this Registration Statement
by reference:

      1. The Company's Annual Report on Form 10-K for the fiscal year ended
         December 31, 1999.

      2. The Company's Quarterly Reports on Form 10-Q for the quarters ended
         March 31, 2000, June 30, 2000 and September 30, 2000.

      3. The description of the Company's Common Stock set forth under the
         caption "Description of Registrant's Securities to be Registered" in
         the Company's Registration Statement on Form 8-A (No. 0-15846) filed
         under the Securities Exchange Act of 1934, as amended (the "Exchange
         Act"), and any reports or amendments to the foregoing filed with the
         Securities and Exchange Commission for the purpose of updating such
         description.

      4. All documents filed by the Company pursuant to Sections 13, 14, or
         15(d) of the Exchange Act subsequent to the date of this Registration
         Statement and before the Company files a post-effective amendment
         hereto which indicates that all shares of Common Stock being offered
         pursuant to this Registration Statement have been sold or which
         deregisters all shares of Common Stock then remaining unsold.

ITEM 4.  DESCRIPTION OF SECURITIES

      Not Applicable.

ITEM 5.  INTERESTS OF NAMED EXPERTS AND COUNSEL

      Certain partners and attorneys associated with Neal, Gerber & Eisenberg
own shares of Common Stock.

ITEM 6.  INDEMNIFICATION OF DIRECTORS AND OFFICERS

      Section 145 of the Delaware General Corporation Law empowers the Company
to indemnify officers and directors in certain instances. Article Seventh,
Section 2 of the Restated Certificate of Incorporation of the Company provides
as follows: "The directors, as well as the officers, employees and agents of the
Company shall be indemnified by the Company to the fullest extent permitted by
the Delaware General Corporation Law as the same exists or may hereafter be
amended." As a consequence, directors of the Company will be insulated from
liability for monetary damages for breach of fiduciary duty as a director,
including monetary liabilities for negligent or grossly negligent business
decisions, except for liability (i) for any breach of the director's duty of
loyalty to the Company or its stockholders, (ii) for acts or omissions not in
good faith or which involve intentional misconduct or a knowing violation of
law, (iii) for the payment of unlawful dividends or unlawful stock repurchases
or redemptions, or (iv) for transactions in which the director received an
improper personal benefit. The exculpation provided with respect to liability by
the foregoing is effective for actions taken after April 16, 1987.

      The By-Laws of the Company contain provisions whereby the Company will
indemnify its directors, officers, employees and agents against liabilities
incurred in connection with, and related expenses resulting from, any claim,
action or suit brought against such persons as a result of their relationship
with the Company, provided that it is determined that such persons acted in
accordance with a stated standard of conduct in connection with the acts or
events upon which such claim, action or suit is based. Such discrimination will
be made either by quorum of disinterested directors, if available, or by
independent legal counsel in a written opinion, or by the vote of the Company's
stockholders. The finding of either criminal or civil liability on the part of
such persons in connection


<PAGE>   3

with such acts or events is not necessarily determinative of the question of
whether such persons have met the required standard of conduct and are,
accordingly, entitled to be indemnified.

      The Company has purchased for the benefit of its officers and directors an
insurance policy, whereby the insurance company agrees, among other things, to
make payment to the Company in the event any such officer or director becomes
legally obligated to make a payment in connection with an alleged wrongful act.
Wrongful acts means any breach of duty, neglect, error, misstatement, misleading
statement, omission or other act done or wrongfully attempted by an officer or
director of the Company.

ITEM 7.  EXEMPTION FROM REGISTRATION CLAIMED

      Not Applicable.

ITEM 8.  EXHIBITS

Exhibit
 Number    Description of Document                                      Page No.
-------    -----------------------                                      -------

  4        2000 Stock Option Plan ....................................    ____

  5        Opinion of Neal, Gerber & Eisenberg .......................    ____

  23.1     Consent of Deloitte & Touche LLP ......... ................    ____

  23.2     Consent of Neal, Gerber & Eisenberg (included in
           Exhibit 5 to this Registration Statement) .................    ____

  24       Powers of Attorney ........................................    ____


ITEM 9.  UNDERTAKINGS

         The undersigned hereby undertakes:

         1.  To file, during any period in which offers or sales are being made,
             a post-effective amendment to this Registration Statement to
             include any material information with respect to the plan of
             distribution not previously disclosed in the Registration Statement
             or any material change to such information in the Registration
             Statement.

         2.  That, for the purpose of determining any liability under the
             Securities Act of 1933, as amended (the "Act"), each post-effective
             amendment to this Registration Statement shall be deemed to be a
             new Registration Statement relating to the securities offered
             therein, and the offering of such securities at that time shall be
             deemed to be the initial bona fide offering thereof.

         3.  To remove from registration by means of a post-effective amendment
             any of the securities being registered which remain unsold at the
             termination of the offering.

         4.  That, for purposes of determining any liability under the Act, each
             filing of the Company's annual report pursuant to Sections 13(a) or
             15(d) of the Exchange Act that is incorporated by reference in this
             Registration Statement shall be deemed to be a new registration
             statement relating to the securities offered therein, and the
             offering of such securities at that time shall be deemed to be the
             initial bona fide offering thereof.

         5.  To deliver or cause to be delivered with the prospectus, to each
             employee to whom the prospectus is sent or given, a copy of the
             Company's annual report to stockholders for its last fiscal year,
             unless such employee has otherwise received a copy of such report,
             in which case the Company shall state in the prospectus that it
             will promptly furnish, without charge, a copy of such report on

<PAGE>   4

             the written request of the employee. If the last fiscal year of the
             Company has ended within 120 days prior to the use of the
             prospectus, the annual report of the Company for the preceding
             fiscal year may be so delivered, but within such 120-day period the
             annual report for the last fiscal year will be furnished to such
             employee.

         6.  To transmit or cause to be transmitted to all employees
             participating in the plan who do not otherwise receive such
             material as stockholders of the Company, at the time and in the
             manner as such material is sent to its stockholders, copies of all
             reports, proxy statement and other communications distributed to
             its stockholders generally.

         Insofar as indemnification for liabilities arising under the Act may be
permitted to directors, officers or persons controlling the Company pursuant to
the Delaware General Corporation Law, the Restated Certificate of Incorporation
of the Company, the By-Laws of the Company or otherwise, the Company has been
advised that in the opinion of the Securities and Exchange Commission such
indemnification is against public policy as expressed in the Act and is therefor
unenforceable. In the event that a claim for indemnification against such
liabilities (other than the payment by the Company of expenses incurred or paid
by a director, officer or controlling person of the Company in the successful
defense of any action suit or proceeding) is asserted by such director, officer
or controlling person in connection with the securities being registered, the
Company will, unless in the opinion of its counsel the matter has been settled
by controlling precedent, submit to a court of appropriate jurisdiction the
question whether such indemnification by it is against public policy as
expressed in the Act and will be governed by the final adjudication of such
issue.


<PAGE>   5
                                   SIGNATURES

         Pursuant to the requirements of the Securities Act of 1933, as amended,
the Registrant certifies that it has reasonable grounds to believe that it meets
all of the requirements for filing on Form S-8 and has duly caused this
Registration Statement to be signed on its behalf by the undersigned, thereunto
duly authorized in the City of Downers Grove, State of Illinois on the 15th day
of March, 2001.


                                                FIRST HEALTH GROUP CORP.,
                                                a Delaware corporation


                                                By: /s/ James C. Smith
                                                   -----------------------------
                                                   James C. Smith,
                                                   Chairman of the Board,
                                                   Chief Executive Officer and
                                                   Director


<PAGE>   6
         Pursuant to the requirements of the Securities Act of 1933, as amended,
this Registration Statement has been signed by the following persons in the
capacities indicated on the 15th day of March, 2001.

      Signature                                       Title
      ---------                                       -----

/s/ James C. Smith
-----------------------------             Chairman of the Board,
James C. Smith                            Chief Executive Officer and Director
                                          (Principal Executive Officer)

/s/ Joseph E. Whitters
-----------------------------             Vice President, Finance,
Joseph E. Whitters                        Chief Financial Officer and
                                          Treasurer (Principal Accounting and
                                          Principal Financial Officer)

/s/ Daniel S. Brunner*
-----------------------------             Director
Daniel S. Brunner

/s/ Michael J. Boskin*
-----------------------------             Director
Michael J. Boskin, Ph. D.

/s/ Robert S. Colman*
-----------------------------             Director
Robert S. Colman

/s/ Ronald H. Galowich*
-----------------------------             Director
Ronald H. Galowich

/s/ Harold S. Handelsman*
-----------------------------             Director
Harold S. Handelsman

/s/ Don Logan*
-----------------------------             Director
Don Logan

/s/ Thomas J. Pritzker*
-----------------------------             Director
Thomas J. Pritzker

/s/ David E. Simon*
-----------------------------             Director
David E. Simon

      /s/ Joseph E. Whitters
* By: -----------------------
      Joseph E. Whitters
      Attorney-in-fact
[{"type": "S-8", "sequence": "1", "filename": "c60766s-8.txt", "description": "SECURITIES TO BE OFFERED TO EMPLOYEES", "secsgml_size_bytes": 14909}]
{"company-data": {"conformed-name": "FIRST HEALTH GROUP CORP", "cik": "0000812910", "assigned-sic": "6411", "irs-number": "363307583", "state-of-incorporation": "DE", "fiscal-year-end": "1231"}, "filing-values": {"form-type": "S-8", "act": "33", "file-number": "333-57226", "film-number": "1571829"}, "business-address": {"street1": "3200 HIGHLAND AVE", "street2": "HEALTH COMPARE CORP", "city": "DOWNERS GROVE", "state": "IL", "zip": "60515", "phone": "6302417900"}, "mail-address": {"street1": "3200 HIGHLAND AVENUE", "street2": "3200 HIGHLAND AVENUE", "city": "DOWNERS GROVE", "state": "IL", "zip": "60515"}, "former-company": {"former-conformed-name": "HEALTHCARE COMPARE CORP/DE/", "date-changed": "19920703"}}
1

================================================================================
     As filed with the Securities and Exchange Commission on March 19, 2001

                                                    Registration No. 333-_______

                                  UNITED STATES
                       SECURITIES AND EXCHANGE COMMISSION

                             WASHINGTON, D.C. 20549

                                ---------------

                                    FORM S-8

             REGISTRATION STATEMENT UNDER THE SECURITIES ACT OF 1933

                                ---------------

                            FIRST HEALTH GROUP CORP.

             (Exact name of Registrant as specified in its charter)

             DELAWARE                                           36-3307583
  (State or other jurisdiction                                (I.R.S. Employer
of incorporation or organization)                            Identification No.)

                              3200 HIGHLAND AVENUE
                          DOWNERS GROVE, ILLINOIS 60515
                                 (630) 737-7900

    (Address, including zip code, and telephone number, including area code,
                       of Registrant's executive offices)

                                ---------------

                 FIRST HEALTH GROUP CORP. 2000 STOCK OPTION PLAN

                            (Full title of the plan)

                            WILLIAM M. HOLZMAN, ESQ.
                            NEAL, GERBER & EISENBERG
                            TWO NORTH LASALLE STREET
                             CHICAGO, ILLINOIS 60602
                                 (312) 269-8000

            (Name, address, including zip code, and telephone number,
                   including area code, of agent for service)

                                ---------------

                        CALCULATION OF REGISTRATION FEE
--------------------------------------------------------------------------------
       TITLE OF SECURITIES             PROPOSED MAXIMUM              AMOUNT OF
        TO BE REGISTERED           AGGREGATE OFFERING PRICE         REGISTRATION
--------------------------------------------------------------------------------
          Common Stock,                 $ 39,812,500 (1)             $9,954.00
         $0.01 par value
--------------------------------------------------------------------------------
(1)   Estimated solely for the purpose of calculating the registration fee
      pursuant to Rules 457(c) and 457(h) under the Securities Act of 1933, as
      amended, on the basis of the average of the high and low prices of the
      Corporation's Common Stock as reported on the Nasdaq National Market
      System on March 15, 2001.
2
                                     PART II

               INFORMATION REQUIRED IN THE REGISTRATION STATEMENT

ITEM 3.  INCORPORATION OF DOCUMENTS BY REFERENCE

      The following documents are incorporated into this Registration Statement
by reference:

      1. The Company's Annual Report on Form 10-K for the fiscal year ended
         December 31, 1999.

      2. The Company's Quarterly Reports on Form 10-Q for the quarters ended
         March 31, 2000, June 30, 2000 and September 30, 2000.

      3. The description of the Company's Common Stock set forth under the
         caption "Description of Registrant's Securities to be Registered" in
         the Company's Registration Statement on Form 8-A (No. 0-15846) filed
         under the Securities Exchange Act of 1934, as amended (the "Exchange
         Act"), and any reports or amendments to the foregoing filed with the
         Securities and Exchange Commission for the purpose of updating such
         description.

      4. All documents filed by the Company pursuant to Sections 13, 14, or
         15(d) of the Exchange Act subsequent to the date of this Registration
         Statement and before the Company files a post-effective amendment
         hereto which indicates that all shares of Common Stock being offered
         pursuant to this Registration Statement have been sold or which
         deregisters all shares of Common Stock then remaining unsold.

ITEM 4.  DESCRIPTION OF SECURITIES

      Not Applicable.

ITEM 5.  INTERESTS OF NAMED EXPERTS AND COUNSEL

      Certain partners and attorneys associated with Neal, Gerber & Eisenberg
own shares of Common Stock.

ITEM 6.  INDEMNIFICATION OF DIRECTORS AND OFFICERS

      Section 145 of the Delaware General Corporation Law empowers the Company
to indemnify officers and directors in certain instances. Article Seventh,
Section 2 of the Restated Certificate of Incorporation of the Company provides
as follows: "The directors, as well as the officers, employees and agents of the
Company shall be indemnified by the Company to the fullest extent permitted by
the Delaware General Corporation Law as the same exists or may hereafter be
amended." As a consequence, directors of the Company will be insulated from
liability for monetary damages for breach of fiduciary duty as a director,
including monetary liabilities for negligent or grossly negligent business
decisions, except for liability (i) for any breach of the director's duty of
loyalty to the Company or its stockholders, (ii) for acts or omissions not in
good faith or which involve intentional misconduct or a knowing violation of
law, (iii) for the payment of unlawful dividends or unlawful stock repurchases
or redemptions, or (iv) for transactions in which the director received an
improper personal benefit. The exculpation provided with respect to liability by
the foregoing is effective for actions taken after April 16, 1987.

      The By-Laws of the Company contain provisions whereby the Company will
indemnify its directors, officers, employees and agents against liabilities
incurred in connection with, and related expenses resulting from, any claim,
action or suit brought against such persons as a result of their relationship
with the Company, provided that it is determined that such persons acted in
accordance with a stated standard of conduct in connection with the acts or
events upon which such claim, action or suit is based. Such discrimination will
be made either by quorum of disinterested directors, if available, or by
independent legal counsel in a written opinion, or by the vote of the Company's
stockholders. The finding of either criminal or civil liability on the part of
such persons in connection
3

with such acts or events is not necessarily determinative of the question of
whether such persons have met the required standard of conduct and are,
accordingly, entitled to be indemnified.

      The Company has purchased for the benefit of its officers and directors an
insurance policy, whereby the insurance company agrees, among other things, to
make payment to the Company in the event any such officer or director becomes
legally obligated to make a payment in connection with an alleged wrongful act.
Wrongful acts means any breach of duty, neglect, error, misstatement, misleading
statement, omission or other act done or wrongfully attempted by an officer or
director of the Company.

ITEM 7.  EXEMPTION FROM REGISTRATION CLAIMED

      Not Applicable.

ITEM 8.  EXHIBITS

Exhibit
 Number    Description of Document                                      Page No.
-------    -----------------------                                      -------

  4        2000 Stock Option Plan ....................................    ____

  5        Opinion of Neal, Gerber & Eisenberg .......................    ____

  23.1     Consent of Deloitte & Touche LLP ......... ................    ____

  23.2     Consent of Neal, Gerber & Eisenberg (included in
           Exhibit 5 to this Registration Statement) .................    ____

  24       Powers of Attorney ........................................    ____

ITEM 9.  UNDERTAKINGS

         The undersigned hereby undertakes:

         1.  To file, during any period in which offers or sales are being made,
             a post-effective amendment to this Registration Statement to
             include any material information with respect to the plan of
             distribution not previously disclosed in the Registration Statement
             or any material change to such information in the Registration
             Statement.

         2.  That, for the purpose of determining any liability under the
             Securities Act of 1933, as amended (the "Act"), each post-effective
             amendment to this Registration Statement shall be deemed to be a
             new Registration Statement relating to the securities offered
             therein, and the offering of such securities at that time shall be
             deemed to be the initial bona fide offering thereof.

         3.  To remove from registration by means of a post-effective amendment
             any of the securities being registered which remain unsold at the
             termination of the offering.

         4.  That, for purposes of determining any liability under the Act, each
             filing of the Company's annual report pursuant to Sections 13(a) or
             15(d) of the Exchange Act that is incorporated by reference in this
             Registration Statement shall be deemed to be a new registration
             statement relating to the securities offered therein, and the
             offering of such securities at that time shall be deemed to be the
             initial bona fide offering thereof.

         5.  To deliver or cause to be delivered with the prospectus, to each
             employee to whom the prospectus is sent or given, a copy of the
             Company's annual report to stockholders for its last fiscal year,
             unless such employee has otherwise received a copy of such report,
             in which case the Company shall state in the prospectus that it
             will promptly furnish, without charge, a copy of such report on
4

             the written request of the employee. If the last fiscal year of the
             Company has ended within 120 days prior to the use of the
             prospectus, the annual report of the Company for the preceding
             fiscal year may be so delivered, but within such 120-day period the
             annual report for the last fiscal year will be furnished to such
             employee.

         6.  To transmit or cause to be transmitted to all employees
             participating in the plan who do not otherwise receive such
             material as stockholders of the Company, at the time and in the
             manner as such material is sent to its stockholders, copies of all
             reports, proxy statement and other communications distributed to
             its stockholders generally.

         Insofar as indemnification for liabilities arising under the Act may be
permitted to directors, officers or persons controlling the Company pursuant to
the Delaware General Corporation Law, the Restated Certificate of Incorporation
of the Company, the By-Laws of the Company or otherwise, the Company has been
advised that in the opinion of the Securities and Exchange Commission such
indemnification is against public policy as expressed in the Act and is therefor
unenforceable. In the event that a claim for indemnification against such
liabilities (other than the payment by the Company of expenses incurred or paid
by a director, officer or controlling person of the Company in the successful
defense of any action suit or proceeding) is asserted by such director, officer
or controlling person in connection with the securities being registered, the
Company will, unless in the opinion of its counsel the matter has been settled
by controlling precedent, submit to a court of appropriate jurisdiction the
question whether such indemnification by it is against public policy as
expressed in the Act and will be governed by the final adjudication of such
issue.
5
                                   SIGNATURES

         Pursuant to the requirements of the Securities Act of 1933, as amended,
the Registrant certifies that it has reasonable grounds to believe that it meets
all of the requirements for filing on Form S-8 and has duly caused this
Registration Statement to be signed on its behalf by the undersigned, thereunto
duly authorized in the City of Downers Grove, State of Illinois on the 15th day
of March, 2001.

                                                FIRST HEALTH GROUP CORP.,
                                                a Delaware corporation

                                                By: /s/ James C. Smith
                                                   -----------------------------
                                                   James C. Smith,
                                                   Chairman of the Board,
                                                   Chief Executive Officer and
                                                   Director
6
         Pursuant to the requirements of the Securities Act of 1933, as amended,
this Registration Statement has been signed by the following persons in the
capacities indicated on the 15th day of March, 2001.

      Signature                                       Title
      ---------                                       -----

/s/ James C. Smith
-----------------------------             Chairman of the Board,
James C. Smith                            Chief Executive Officer and Director
                                          (Principal Executive Officer)

/s/ Joseph E. Whitters
-----------------------------             Vice President, Finance,
Joseph E. Whitters                        Chief Financial Officer and
                                          Treasurer (Principal Accounting and
                                          Principal Financial Officer)

/s/ Daniel S. Brunner*
-----------------------------             Director
Daniel S. Brunner

/s/ Michael J. Boskin*
-----------------------------             Director
Michael J. Boskin, Ph. D.

/s/ Robert S. Colman*
-----------------------------             Director
Robert S. Colman

/s/ Ronald H. Galowich*
-----------------------------             Director
Ronald H. Galowich

/s/ Harold S. Handelsman*
-----------------------------             Director
Harold S. Handelsman

/s/ Don Logan*
-----------------------------             Director
Don Logan

/s/ Thomas J. Pritzker*
-----------------------------             Director
Thomas J. Pritzker

/s/ David E. Simon*
-----------------------------             Director
David E. Simon

      /s/ Joseph E. Whitters
* By: -----------------------
      Joseph E. Whitters
      Attorney-in-fact