Exhibit 31.1

				CERTIFICATION



I, Dan R. Carmichael, certify that:

	1.  I have reviewed this quarterly report on Form 10-Q of
	    Ohio Casualty Corporation;

	2.  Based on my knowledge, this report does not contain any
	    untrue statement of a material fact or omit to state a
	    material fact necessary to make the statements made, in
	    light of the circumstances under which such statements
	    were made, not misleading with respect to the period
	    covered by this report;

	3.  Based on my knowledge, the financial statements, and
	    other financial information included in this report,
	    fairly present in all material respects the financial
	    condition, results of operations and cash flows of the
	    registrant as of, and for, the periods presented in this
	    report;

	4.  The registrant's other certifying officer(s) and I are
	    responsible for establishing and maintaining disclosure
	    controls and procedures (as defined in Exchange Act Rules
	    13a-15(e) and 15d-15(e)) and internal control over
	    financial reporting (as defined in exchange Act Rules
	    13a-15(f) and 15d-15(f)) for the Registrant and have:

	       (a)  Designed such disclosure controls and procedures,
		    or caused such disclosure controls and procedures
		    to be designed under our supervision, to ensure that
		    material information relating to the registrant,
		    including its consolidated subsidiaries, is made
		    known to us by others within those entities,
		    particularly during the period in which this report
		    is being prepared;

	       (b)  Designed such internal control over financial reporting,
		    or caused such internal control over financial reporting
		    to be designed under our supervision, to provide
		    reasonable assurance regarding the reliability of
		    financial reporting and the preparation of financial
		    statements for external purposes in accordance with
		    generally accepted accounting principles;

	       (c)  Evaluated the effectiveness of the registrant's
		    disclosure controls and procedures and presented in this
		    report our conclusions about the effectiveness of the
		    disclosure controls and procedures, as of the end of the
		    period covered by this report based on such evaluation;
		    and

	       (d)  Disclosed in this report any change in the registrant's
		    internal control over financial reporting that occurred
		    during the registrant's most recent fiscal quarter (the
		    registrant's fourth fiscal quarter in the case of an
		    annual report) that has materially affected, or is
		    reasonably likely to materially affect, the registrant's
		    internal control over financial reporting; and

	5.  The registrant's other certifying officer(s) and I have disclosed,
	    based on our most recent evaluation, of internal control over
	    financial reporting, to the registrant's auditors and the audit
	    committee of the registrant's board of directors (or persons
	    performing the equivalent functions):

	       (a)  All significant deficiencies and material weaknesses in
		    the design or operation of internal control over
		    financial reporting which are reasonably likely to
		    adversely affect the registrant's ability to record,
		    process, summarize and report financial information; and

	       (b)  Any fraud, whether or not material, that involves
		    management or other employees who have a significant role
		    in the registrant's internal control over financial
		    reporting.




Date:  July 26, 2005                                 /s/Dan R. Carmichael
						     -------------------------
						     Dan R. Carmichael
						     President and Chief
						     Executive Officer