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                                                                    EXHIBIT 4.5

                           THE PROGRESSIVE CORPORATION

                                       and

                     STATE STREET BANK AND TRUST COMPANY, as
                                Successor Trustee

                          THIRD SUPPLEMENTAL INDENTURE

                          6.375% Senior Notes due 2012

         THIS THIRD SUPPLEMENTAL INDENTURE, dated as of December 7, 2001,
between THE PROGRESSIVE CORPORATION, an Ohio corporation (the "ISSUER") and
STATE STREET BANK AND TRUST COMPANY, a Massachusetts trust company ("SSB"), in
its capacity as Successor Trustee.

                                      W I T N E S S E T H:

         WHEREAS, the Issuer entered into an Indenture, dated as of September
15, 1993 (as supplemented by the First Supplemental Indenture, dated as of March
15, 1996, the "INDENTURE"), with the First National Bank of Boston, in its
capacity as Trustee, pursuant to which the Issuer may from time to time issue
its unsecured debentures, notes and other evidences of indebtedness in one or
more series; and

         WHEREAS, the Issuer entered into a Supplemental Indenture, dated as of
March 15, 1996, confirming the succession of SSB as trustee under the Indenture;
and

         WHEREAS, the Issuer entered into a Second Supplemental Indenture, dated
as of February 26, 1999;

         WHEREAS, Article Eight of the Indenture provides for various matters
with respect to any series of Securities issued under the Indenture to be
established in an indenture supplemental to the Indenture; and

         WHEREAS, Section 8.1(c) of the Indenture provides that the Issuer, when
authorized by its Board of Directors, and the Trustee may from time to time and
at any time enter into an indenture supplemental to the Indenture to add on to
the covenants of the Issuer certain further covenants, restrictions, conditions
or provisions.

         NOW THEREFORE:




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         In consideration of the premises and other good and valuable
consideration, the parties hereto mutually covenant and agree as follows:

                                    ARTICLE 1
                       RELATION TO INDENTURE; DEFINITIONS

         SECTION 1.01. Integral Part. This Third Supplemental Indenture
constitutes an integral part of the Indenture.

         SECTION 1.02. General Definitions. For all purposes of this Third
Supplemental Indenture:

         (a) capitalized terms used herein without definition shall have the
meanings specified in the Indenture;

         (b) all references herein to Articles and Sections, unless otherwise
specified, refer to the corresponding Articles and Sections of this Third
Supplemental Indenture; and

         (c) the terms "HEREIN", "HEREOF", "HEREUNDER" and other words of
similar import refer to this Third Supplemental Indenture.

         SECTION 1.03. Definitions. The following definitions shall apply to
this Third Supplemental Indenture:

         "CONSOLIDATED TANGIBLE NET WORTH" means, at any date, the total assets
appearing on the consolidated balance sheet of the Issuer and its consolidated
subsidiaries as of the end of the then most recent fiscal quarter of the Issuer,
prepared in accordance with generally accepted accounting principles, less the
sum of (a) the total liabilities appearing on such balance sheet and (b)
intangible assets. "INTANGIBLE ASSETS" means, for the purposes of this
definition, the value, as shown on or reflected in such balance sheet, of (i)
all trade names, trademarks, licenses, patents, copyrights and goodwill, (ii)
organizational costs and (iii) unamortized debt discount and expense, less
unamortized premium.

         "DESIGNATED SECURITIES" means the series of Securities designated by
the Issuer as its "6.375% Senior Notes due 2012".

         "DESIGNATED SUBSIDIARY" means (i) Progressive Casualty Insurance
Company, an Ohio corporation, so long as it remains a subsidiary of the Issuer,
(ii) any other consolidated subsidiary of the Issuer the assets of which
constitute 10% or more of the Total Assets, and (iii) any subsidiary that is a
successor to all or substantially all of the business or properties of any such
subsidiary.




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         "TOTAL ASSETS" means, at any date, the total assets appearing on the
consolidated balance sheet of the Issuer and its consolidated subsidiaries as of
the end of the then most recent fiscal quarter of the Issuer, prepared in
accordance with generally accepted accounting principles.

                                    ARTICLE 2
                              ADDITIONAL COVENANTS

       SECTION 2.01. Limitation on Liens. The Issuer will not, nor will it
permit any Designated Subsidiary to, incur, issue, assume or guarantee any
indebtedness for money borrowed if (i) that indebtedness is secured by a pledge,
mortgage, deed of trust or other lien on any shares of stock or indebtedness of
any Designated Subsidiary (a "LIEN"), and (ii) the aggregate amount of the
indebtedness so secured exceeds an amount equal to 15% of the Issuer's
Consolidated Tangible Net Worth, unless the Designated Securities are also
secured equally and ratably with such other indebtedness. For purposes of this
restriction, a "LIEN" will not include the pledge to, or deposit with, any state
or provincial insurance regulatory authorities of any investment securities by
the Issuer or any of its subsidiaries.

         The foregoing restriction shall not apply to indebtedness secured by:

         (a) Liens on any shares of stock or indebtedness of or acquired from a
corporation merged or consolidated with or into, or otherwise acquired by, the
Issuer or a Designated Subsidiary;

         (b) Liens to secure indebtedness of a Designated Subsidiary to the
Issuer or to another Designated Subsidiary, but only as long as such
indebtedness is owned or held by the Issuer or a Designated Subsidiary; and

         (c) Any extension, renewal or replacement (or successive extensions,
renewals or replacements), in whole or in part, of any lien referred to in (a)
and (b).

         SECTION 2.02. Consolidation, Merger, Sale, Conveyance and Lease. The
Issuer will not consolidate or merge with or into any other Person or Persons,
or sell, convey or lease all or substantially all of its property to any other
Person, unless:

         (a) the Person formed by such consolidation, or into which the Issuer
is merged or which acquires or leases all or substantially all of the property
of the Issuer, is a corporation or other entity organized under the laws of the
United States, any state thereof or the District of Columbia, and such Person
expressly assumes the Issuer's obligations under the Designated Securities and
the Indenture; and

         (b) immediately after giving effect to the transaction, no Event of
Default exists.

         This restriction shall not apply if the Issuer is the Person that
survives any such transaction.






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         In the event of a conflict between any provision in this Section and
any provision in Article 9 of the Indenture, Article 9 of the Indenture shall
govern.

                                    ARTICLE 3
                            MISCELLANEOUS PROVISIONS

         SECTION 3.01. Applicability of this Third Supplemental Indenture. The
provisions of this Third Supplemental Indenture will be applicable solely to the
Designated Securities.

         SECTION 3.02. Adoption, Ratification and Confirmation. The Indenture,
as supplemented by this Third Supplemental Indenture, is in all respects hereby
adopted, ratified and confirmed.

         SECTION 3.03. Counterparts. This Third Supplemental Indenture may be
executed in any number of counterparts, each of which when so executed shall be
deemed an original; and all such counterparts shall together constitute but one
and the same instrument.

         SECTION 3.04. GOVERNING LAW. THIS THIRD SUPPLEMENTAL INDENTURE SHALL BE
GOVERNED BY AND CONSTRUED IN ACCORDANCE WITH THE LAWS OF THE STATE OF NEW YORK.













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       IN WITNESS WHEREOF, the parties hereto have caused this Third
Supplemental Indenture to be duly executed and their respective corporate seals
to be hereunto fixed and attested as of the day and year first written above.

                                              THE PROGRESSIVE CORPORATION

                                              By:  /s/ Stephen D. Peterson
                                                  -------------------------
                                                   Stephen D. Peterson
                                                   Treasurer

Attest:

By: /s/ Charles E. Jarrett
   -----------------------------
    Charles E. Jarrett
    Secretary

                                              STATE STREET BANK AND TRUST
                                                 COMPANY, as Successor Trustee

                                              By:  /s/ Dori Ann Seakas
                                                  -------------------------
                                                   Name:  Dori Ann Seakas
                                                   Title: Officer

Attest:

By: /s/ Patrick E. Thebado
   -----------------------------
    Name:  Patrick E. Thebado
    Title: Vice President









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STATE OF OHIO       )
                    ) ss:
COUNTY OF CUYAHOGA  )

         On this __th day of December, 2001, before me personally came Stephen
D. Peterson, to me personally known, who, being by me duly sworn, did depose and
say that he is a resident of Cuyahoga County, Ohio; that he is an officer of THE
PROGRESSIVE CORPORATION, one of the corporations described in and which executed
the above instrument; that he knows the corporate seal of said corporation; that
the seal affixed to said instrument is such corporate seal; that it was so
affixed by authority of the Board of Directors of said corporation, and that he
signed his name thereto by like authority.

                                                    ____________________________
                                                    Notary Public
                                                    My commission expires:

[Notarial Seal]

STATE OF MASSACHUSETTS     )
                           ) ss.:
COUNTY OF SUFFOLK          )

       On this __th day of December, 2001, before me personally came , to me
personally known, who, being by me duly sworn, did depose and say that he is a
resident of Bristol County, Massachusetts; that he is an authorized officer of
STATE STREET BANK AND TRUST COMPANY, one of the corporations described in and
which executed the above instrument; that he knows the corporate seal of said
corporation; that the seal affixed to said instruments is such corporate seal;
that it was so affixed by authority of the Board of Directors of said
corporation, and that he signed her name thereto by like authority.



                                                    ____________________________
                                                    Notary Public
                                                    My commission expires:

[Notary Seal]













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