SECURITIES AND EXCHANGE COMMISSION
                            Washington, D. C. 20549

                                    FORM 8-K

                                 CURRENT REPORT

                       Pursuant to Section 13 or 15(d) of
                      The Securities Exchange Act of 1934

        Date of Report (Date of earliest event reported) March 29, 2005

                           OHIO CASUALTY CORPORATION
             (Exact name of registrant as specified in its charter)

                                      OHIO
         (State or other jurisdiction of incorporation or organization)

                         Commission File Number 0-5544


                                   31-0783294
                      (I.R.S. Employer Identification No.)


                                9450 Seward Road
                                Fairfield, Ohio
                    (Address of principal executive offices)

                                     45014
                                   (Zip Code)

                                 (513) 603-2400
                        (Registrant's telephone number)

                                 Not Applicable
         (Former name or former address, if changed since last report)

Check the appropriate box below if the Form 8-K filing is intended to
simultaneously satisfy the filing obligation of the registrant under any of the
following provisions (see General Instruction A.2. below):

[ ] Written communications pursuant to Rule 425 under the Securities Act
    (17 CFR 230.425)

[ ] Soliciting material pursuant to Rule 14a-12 under the Exchange Act
    (17 CFR 240.14a-12)

[ ] Pre-commencement communications pursuant to Rule 14d-2(b) under the
    Exchange Act (17 CFR 240.14d-2(b))

[ ] Pre-commencement communications pursuant to Rule 13e-4(c) under the
    Exchange Act (17 CFR 240.13e-4(c))


<PAGE>

ITEM 1.01 ENTRY INTO A MATERIAL DEFINITIVE AGREEMENT.

         On March 25, 2005, Ohio Casualty Corporation (the "Company") entered
into an indenture (the "Indenture") with HSBC Bank USA, National Association,
as trustee, in connection with the Company's offer to exchange (the "Exchange
Offer") new 5.00% Convertible Notes due 2022 (the "New Notes") for all of the
Company's outstanding 5.00% Convertible Notes due 2022 (the "Old Notes").

         On March 25, 2005, the New Notes were issued pursuant to the Indenture
to all holders of Old Notes who had properly tendered Old Notes in the Exchange
Offer. A description of the material terms of the New Notes is incorporated
herein by reference to the information under the headings "Summary Description
of the Notes" and "Description of the New Notes" in the Company's offering
memorandum (the "Offering Memorandum") dated February 22, 2005, which was filed
as Exhibit 12(a)(1)(i) to the Company's Schedule TO dated February 22, 2005, as
amended and supplemented by Amendment No. 1 thereto, filed on March 17, 2005
and by Amendment No. 2 thereto, filed on March 22, 2005 (as amended and
supplemented, the "Schedule TO"). The Indenture was qualified pursuant to the
Company's Form T-3 Application for Qualification of Trust Indenture (SEC File
No. 022-28773). The Indenture is filed hereto as Exhibit 4.1.

ITEM 2.03. CREATION OF A DIRECT FINANCIAL OBLIGATION OR AN OBLIGATION UNDER AN
OFF-BALANCE SHEET ARRANGEMENT OF A REGISTRANT.

         The response to Item 1.01 above is incorporated herein.

ITEM 3.02. UNREGISTERED SALES OF EQUITY SECURITIES.

         The Exchange Offer expired at midnight on Monday, March 21, 2005.
Pursuant to the Exchange Offer, approximately $65,557,000 aggregate principal
amount, representing approximately 35.6% of the outstanding principal amount of
the Old Notes, were exchanged for New Notes. The Company accepted all validly
tendered Old Notes and, in exchange, issued a like principal amount of the New
Notes and paid a cash exchange fee of $3.50 for each $1,000 principal amount of
the Old Notes exchanged. The Company did not receive any proceeds from the
issuance of the New Notes.

         The New Notes were issued solely to existing security holders of the
Company pursuant to the exemption from registration under Section 3(a)(9) of
the Securities Act of 1933, as amended. The Company did not pay or give,
directly or indirectly, any commission or other remuneration, including
underwriting discounts, to any broker, dealer, salesman or other person for
soliciting tenders of the Old Notes in connection with the Exchange Offer, and
the Company did not retain any dealer, manager or other agent to solicit
tenders with respect to the Exchange Offer.

ITEM 9.01. FINANCIAL STATEMENTS AND EXHIBITS.

(c) Exhibits.

4.1 Indenture dated as of March 25, 2005 between Ohio Casualty Corporation, as
Issuer, and HSBC Bank USA, National Association, as Trustee.


                                   SIGNATURE

         Pursuant to the requirements of the Securities Exchange Act of 1934,
the registrant has duly caused this report to be signed on its behalf by the
undersigned hereunto duly authorized.


                                        OHIO CASUALTY CORPORATION
                                        (Registrant)

                                        /s/ Debra K. Crane
                                        --------------------------------------
                                        Debra K. Crane, Esq.
                                        Senior Vice President, General Counsel
                                          and Secretary

Date: March 29, 2005


EXHIBIT INDEX

Exhibit Number    Exhibit

4.1               Indenture dated as of March 25, 2005 between Ohio Casualty
                  Corporation, as Issuer, and HSBC Bank USA, National
                  Association, as Trustee.
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{"company-data": {"conformed-name": "OHIO CASUALTY CORP", "cik": "0000073952", "assigned-sic": "6331", "irs-number": "310783294", "state-of-incorporation": "OH", "fiscal-year-end": "1231"}, "filing-values": {"form-type": "8-K", "act": "34", "file-number": "000-05544", "film-number": "05709321"}, "business-address": {"street1": "9450 SEWARD ROAD", "city": "FAIRFIELD", "state": "OH", "zip": "45014", "phone": "5136032400"}, "mail-address": {"street1": "9450 SEWARD ROAD", "city": "FAIRFIELD", "state": "OH", "zip": "45014"}}
SECURITIES AND EXCHANGE COMMISSION
                            Washington, D. C. 20549

                                    FORM 8-K

                                 CURRENT REPORT

                       Pursuant to Section 13 or 15(d) of
                      The Securities Exchange Act of 1934

        Date of Report (Date of earliest event reported) March 29, 2005

                           OHIO CASUALTY CORPORATION
             (Exact name of registrant as specified in its charter)

                                      OHIO
         (State or other jurisdiction of incorporation or organization)

                         Commission File Number 0-5544

                                   31-0783294
                      (I.R.S. Employer Identification No.)

                                9450 Seward Road
                                Fairfield, Ohio
                    (Address of principal executive offices)

                                     45014
                                   (Zip Code)

                                 (513) 603-2400
                        (Registrant's telephone number)

                                 Not Applicable
         (Former name or former address, if changed since last report)

Check the appropriate box below if the Form 8-K filing is intended to
simultaneously satisfy the filing obligation of the registrant under any of the
following provisions (see General Instruction A.2. below):

[ ] Written communications pursuant to Rule 425 under the Securities Act
    (17 CFR 230.425)

[ ] Soliciting material pursuant to Rule 14a-12 under the Exchange Act
    (17 CFR 240.14a-12)

[ ] Pre-commencement communications pursuant to Rule 14d-2(b) under the
    Exchange Act (17 CFR 240.14d-2(b))

[ ] Pre-commencement communications pursuant to Rule 13e-4(c) under the
    Exchange Act (17 CFR 240.13e-4(c))
ITEM 1.01 ENTRY INTO A MATERIAL DEFINITIVE AGREEMENT.

         On March 25, 2005, Ohio Casualty Corporation (the "Company") entered
into an indenture (the "Indenture") with HSBC Bank USA, National Association,
as trustee, in connection with the Company's offer to exchange (the "Exchange
Offer") new 5.00% Convertible Notes due 2022 (the "New Notes") for all of the
Company's outstanding 5.00% Convertible Notes due 2022 (the "Old Notes").

         On March 25, 2005, the New Notes were issued pursuant to the Indenture
to all holders of Old Notes who had properly tendered Old Notes in the Exchange
Offer. A description of the material terms of the New Notes is incorporated
herein by reference to the information under the headings "Summary Description
of the Notes" and "Description of the New Notes" in the Company's offering
memorandum (the "Offering Memorandum") dated February 22, 2005, which was filed
as Exhibit 12(a)(1)(i) to the Company's Schedule TO dated February 22, 2005, as
amended and supplemented by Amendment No. 1 thereto, filed on March 17, 2005
and by Amendment No. 2 thereto, filed on March 22, 2005 (as amended and
supplemented, the "Schedule TO"). The Indenture was qualified pursuant to the
Company's Form T-3 Application for Qualification of Trust Indenture (SEC File
No. 022-28773). The Indenture is filed hereto as Exhibit 4.1.

ITEM 2.03. CREATION OF A DIRECT FINANCIAL OBLIGATION OR AN OBLIGATION UNDER AN
OFF-BALANCE SHEET ARRANGEMENT OF A REGISTRANT.

         The response to Item 1.01 above is incorporated herein.

ITEM 3.02. UNREGISTERED SALES OF EQUITY SECURITIES.

         The Exchange Offer expired at midnight on Monday, March 21, 2005.
Pursuant to the Exchange Offer, approximately $65,557,000 aggregate principal
amount, representing approximately 35.6% of the outstanding principal amount of
the Old Notes, were exchanged for New Notes. The Company accepted all validly
tendered Old Notes and, in exchange, issued a like principal amount of the New
Notes and paid a cash exchange fee of $3.50 for each $1,000 principal amount of
the Old Notes exchanged. The Company did not receive any proceeds from the
issuance of the New Notes.

         The New Notes were issued solely to existing security holders of the
Company pursuant to the exemption from registration under Section 3(a)(9) of
the Securities Act of 1933, as amended. The Company did not pay or give,
directly or indirectly, any commission or other remuneration, including
underwriting discounts, to any broker, dealer, salesman or other person for
soliciting tenders of the Old Notes in connection with the Exchange Offer, and
the Company did not retain any dealer, manager or other agent to solicit
tenders with respect to the Exchange Offer.

ITEM 9.01. FINANCIAL STATEMENTS AND EXHIBITS.

(c) Exhibits.

4.1 Indenture dated as of March 25, 2005 between Ohio Casualty Corporation, as
Issuer, and HSBC Bank USA, National Association, as Trustee.

                                   SIGNATURE

         Pursuant to the requirements of the Securities Exchange Act of 1934,
the registrant has duly caused this report to be signed on its behalf by the
undersigned hereunto duly authorized.

                                        OHIO CASUALTY CORPORATION
                                        (Registrant)

                                        /s/ Debra K. Crane
                                        --------------------------------------
                                        Debra K. Crane, Esq.
                                        Senior Vice President, General Counsel
                                          and Secretary

Date: March 29, 2005

EXHIBIT INDEX

Exhibit Number    Exhibit

4.1               Indenture dated as of March 25, 2005 between Ohio Casualty
                  Corporation, as Issuer, and HSBC Bank USA, National
                  Association, as Trustee.