<PAGE>   1





As filed with the Securities and Exchange Commission on April 10, 1995

                                                       Registration No. 33-37707
________________________________________________________________________________
       

                       SECURITIES AND EXCHANGE COMMISSION
                             Washington, D.C. 20549

                         POST-EFFECTIVE AMENDMENT NO. 1
                                       to
                                    FORM S-8
                             REGISTRATION STATEMENT
                                     Under
                           THE SECURITIES ACT OF 1933

                          THE PROGRESSIVE CORPORATION
             (Exact name of registrant as specified in its charter)

           OHIO                                         34-0963169
(State or other jurisdiction of                (I.R.S. Employer Identification
incorporation or organization)                 Number)



             6300 Wilson Mills Road, Mayfield Village, Ohio  44143
             (Address of Principal Executive Offices)   (Zip Code)



                          THE PROGRESSIVE CORPORATION
                       1990 DIRECTORS' STOCK OPTION PLAN
                            (Full title of the plan)

                         David M. Schneider, Secretary
                          The Progressive Corporation
                             6300 Wilson Mills Road
                         Mayfield Village, Ohio  44143
                    (Name and address of agent for service)

                                 (216) 461-5000
         (Telephone number, including area code, of agent for service)



         Pursuant to Rule 416(a) under the Securities Act of 1933, the amount
of securities registered under the Registration Statement shall include an
indeterminate number of additional Common Shares that may become issuable
pursuant to the anti-dilution provisions of the Plan.

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                         POST-EFFECTIVE AMENDMENT NO. 1

                                       TO

                        FORM S-8 REGISTRATION STATEMENT

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

                          THE PROGRESSIVE CORPORATION

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

                      REGISTRATION COVERS SHARES ISSUABLE
                    TO PREVENT DILUTION RESULTING FROM STOCK
                SPLITS, STOCK DIVIDENDS OR SIMILAR TRANSACTIONS



   
         On December 8, 1992, The Progressive Corporation (the "Company")
effected a 3-for-1 split of the Company's Common Shares, $1.00 par value
(the "Common Shares"), in the form of a stock dividend.  Pursuant to the
anti-dilution provisions of The Progressive Corporation 1990 Directors' Stock
Option Plan (the "Plan"), the number of Common Shares issuable under the Plan
was increased from 150,000 to 450,000 as a result of the 3-for-1 stock split.
Accordingly, the Company's Form S-8 Registration Statement (File No. 33-37707)
(the "Registration Statement") is hereby amended to confirm the registration
under the Securities Act of 1933, as amended (the "Act") of all 450,000 Common
Shares issuable under the Plan.  The Registration Statement is further amended
to provide that, pursuant to Rule 416(a) under the Act, the amount of
securities registered under the Registration Statement shall include an
indeterminate number of additional Common Shares that may become issuable
pursuant to the anti-dilution provisions of the Plan.
    





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                                   SIGNATURES


         THE REGISTRANT.  Pursuant to the requirements of the Securities Act of
1933, 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 Post-Effective Amendment No. 1 to the Registration Statement to be signed
on its behalf by the undersigned, thereunto duly authorized, in Mayfield
Village, Ohio, on April 10, 1995.

                                        THE PROGRESSIVE CORPORATION


                                        By: /s/David M. Schneider 
                                            -----------------------------
                                            David M. Schneider, Secretary


                 Pursuant to the requirements of the Securities Act of 1933,
this Post-Effective Amendment No. 1 to the Registration Statement has been
signed by the following persons in the capacities and on the date indicated
below.



<TABLE>
<CAPTION>
         Signature                                       Title
         ---------                                       -----
<S>                                       <C>                                                                                     
         Peter B. Lewis*                   Chairman of the Board, President and Director                                          
- ----------------------------------         (Principal Executive Officer)      
         Peter B.Lewis                      


         /s/Charles B. Chokel              Principal Financial Officer
- ----------------------------------                                    
         Charles B. Chokel


         /s/Jeffrey W. Basch               Principal Accounting Officer
- ----------------------------------                                     
         Jeffrey W. Basch


         Milton N. Allen*                  Director
- ----------------------------------                 
         Milton N. Allen


         B. Charles Ames*                  Director
- ----------------------------------                 
         B. Charles Ames


         Stephen R. Hardis*                Director
- ----------------------------------                 
         Stephen R. Hardis
</TABLE>






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<PAGE>   4


<TABLE>
         <S>                               <C>
         Norman S. Matthews*               Director
- ----------------------------------                 
         Norman S. Matthews

         Donald B. Shackelford*            Director
- ----------------------------------                 
         Donald B. Shackelford

         Paul B. Sigler*                   Director
- ----------------------------------                 
         Paul B. Sigler
</TABLE>



Dated:  April 10, 1995




  *      David M. Schneider, by signing his name hereto, does sign this
         document on behalf of the persons indicated above pursuant to powers
         of attorney duly executed by such persons and filed as an exhibit to
         the Registration Statement.


         By:     /s/David M. Schneider                                         
                 ---------------------
                 David M. Schneider
                 Attorney-in-fact


         Dated:  April 10, 1995





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