EXHIBIT 5

January 27, 2000

Parker-Hannifin Corporation
6035 Parkland Boulevard
Cleveland, Ohio  44124

Re:  Parker Hannifin Corporation 1993 Stock Incentive Program


Ladies and Gentlemen:

         I have acted as counsel for Parker-Hannifin Corporation, an Ohio
corporation (the "Company"), in connection with its 1993 Stock Incentive Program
("Program"). I have examined such documents, records and matters of law as I
have deemed necessary for purposes of this opinion, and based thereon, I am of
the opinion that the shares of the Company's Common Stock, par value $.50 per
share (the "Common Shares"), that may be issued and sold pursuant to the Program
will be duly authorized, validly issued, fully paid and nonassessable when
issued and sold in accordance with the Program, provided that the consideration
received by the Company is at least equal to the par value of the Common Shares.

         I hereby consent to the filing of this opinion as Exhibit 5 to the
Registration Statement on Form S-8 that is being filed by the Company with the
Securities and Exchange Commission regarding the Program.

Very truly yours,

/s/ Thomas A. Piraino, Jr.
Thomas A. Piraino, Jr.
Vice President, General Counsel and Secretary