Exhibit 5.1




                                    March 14, 2005



Cincinnati Financial Corporation
6200 S. Gilmore Road
Fairfield, Ohio 45014


Ladies and Gentlemen:

         We have acted as counsel to Cincinnati Financial Corporation, an Ohio
corporation (the "Company"), in connection with the Registration Statement on
Form S-4 (the "Registration Statement") being filed by the Company with the
Securities and Exchange Commission (the "Commission") under the Securities Act
of 1933, as amended (the "Act"), for the purpose of registering up to
$375,000,000 aggregate principal amount of 6.125% Senior Notes due 2034 (the
"Exchange Notes") issued under an Indenture, dated as of November 1, 2004 (the
"Indenture"), between the Company and The Bank of New York Trust Company, N.A.,
as Trustee (the "Trustee"), as supplemented by the Supplemental Indenture dated
as of November 1, 2004 between the Company and the Trustee (the "First
Supplemental Indenture"). The Exchange Notes will be offered by the Company in
exchange for $375,000,000 aggregate principal amount of 6.125% Senior Notes due
2034 (the "Old Notes"), as contemplated by the Registration Rights Agreement,
dated November 1, 2004, between the Company and the initial purchasers (the
"Registration Rights Agreement").

         In connection with this opinion, we have examined the Registration
Statement, the Indenture and the First Supplemental Indenture, each of which has
been filed with the Commission. We have also examined the originals, or
duplicates or certified or conformed copies, of such records, agreements,
instruments and other documents and have made such other and further
investigations as we have deemed relevant and necessary in connection with the
opinions expressed herein. As to questions of fact material to this opinion, we
have relied upon certificates of public officials and of officers and
representatives of the Company.

         With respect to all of the documents reviewed, we have assumed, without
investigation, the legal capacity of all natural persons, the genuineness of all
signatures, the authenticity of all documents submitted to us as originals and
the conformity to originals of all documents submitted to us as certified or
reproduced copies. As to any facts which we have not independently established
or verified, we have relied upon statements and representations of
representatives of the Company and others. We also have assumed that: (1) each
of the Indenture and the First Supplemental Indenture is the valid and legally
binding obligation of the Trustee; and (2) the Company is validly existing under
the laws of Ohio.

         We have assumed further that (1) the Company has duly authorized,
executed and delivered each of the Indenture and the First Supplemental
Indenture and (2) execution, delivery and performance by the Company of the
Indenture, the First Supplemental Indenture and the Exchange Notes does not and
will not violate the laws of Ohio or any other applicable laws (excepting the
laws of the State of New York and the Federal laws of the United States).

         Based upon the foregoing, and subject to the qualifications and
limitations stated herein, we are of the opinion that when the First
Supplemental Indenture and the Exchange Notes have been duly executed, issued
and delivered, and the Exchange Notes authenticated, in accordance with the
provisions of the Indenture, the First Supplemental Indenture and the
Registration Statement, the Exchange Notes, upon being issued in exchange for
the Old Notes in the exchange offer contemplated by the Registration Statement,
will constitute valid and legally binding obligations of the Company enforceable
against the Company in accordance with their terms, subject to the effects of
(i) bankruptcy, insolvency, fraudulent conveyance, reorganization, moratorium
and other similar laws relating to or affecting creditors' rights generally,
(ii) general equitable principles (whether considered in a proceeding in equity
or at law) and (iii) an implied covenant of good faith and fair dealing.

         We are members of the Bar of the State of New York, and we do not
express any opinion herein concerning any law other than the law of the State of
New York. The foregoing opinion is rendered as of the date hereof, and we assume
no obligation to update such opinion to reflect any facts circumstances which
may hereafter come to our attention or any changes in law which may hereafter
occur.

         We hereby consent to the filing of this opinion letter as Exhibit 5.1
to the Registration Statement and to the reference to this firm under the
caption "Legal Opinions" in the Prospectus constituting part of the Registration
Statement. In giving such consent, we do not thereby admit that we come within
the category of persons whose consent is required under Section 7 of the Act, or
under the rules and regulations of the Commission thereunder.


                                          Very truly yours,


                                          /s/ Dewey Ballantine LLP
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