Exhibit 5 Jones, Day, Reavis & Pogue North Point 901 Lakeside Avenue Cleveland, Ohio 44114 February 14, 2002 Parker-Hannifin Corporation 6035 Parkland Boulevard Cleveland, OH 44124 Re: Registration Statement on Form S-3 filed by Parker-Hannifin Corporation Ladies and Gentlemen: We are acting as counsel for Parker-Hannifin Corporation, an Ohio corporation (the "Company"), in connection with the authorization of the issuance and sale from time to time, on a delayed basis, by the Company of: (i) debt securities ("Debt Securities"), in one or more series, which may be senior, senior subordinated or subordinated in priority of payment, certain of which may be convertible or exchangeable into common shares, par value $.50 per share, of the Company (including the attached common stock purchase rights, "Common Stock"); (ii) shares of Common Stock; (iii) shares of preferred stock, par value $.50 per share, of the Company ("Preferred Stock"), which may be convertible into shares of Common Stock or exchangeable for Debt Securities; (iv) depositary shares representing fractional interests in Preferred Stock (the "Depositary Shares"); (v) warrants to purchase Common Stock, Preferred Stock or Debt Securities ("Warrants"); (vi) contracts to purchase Common Stock or other securities at a future date or dates (the "Stock Purchase Contracts"); and (vii) Stock Purchase Contracts issued as a part of units consisting of a Stock Purchase Contract and Debt Securities, Preferred Stock, Warrants or debt obligations of third parties, including United States treasury securities, securing the holders' obligations to purchase the securities under the Stock Purchase Contracts (the "Stock Purchase Units") (such Debt Securities, Common Stock, Preferred Stock, Depositary Shares, Warrants, Stock Purchase Contracts and Stock Purchase Units are collectively referred to herein as the "Securities" and each, a "Security"), in each case as contemplated by the Company's Registration Statement on Form S-3 to which this opinion has been filed as an exhibit (the "Registration Statement"). The Securities may be issued from time to time pursuant to Rule 415 under the Securities Act of 1933 (the "Securities Act"). In rendering this opinion, we have examined such documents and records, including an examination of originals or copies certified or otherwise identified to our satisfaction, and matters of law as we have deemed necessary for purposes of this opinion. Based upon the foregoing and subject to the assumptions, qualifications and limitations stated herein, we are of the opinion that: 1. The Debt Securities being registered pursuant to the Registration Statement, when issued and delivered as contemplated by the Registration Statement and Parker-Hannifin Corporation February 14, 2002 Page 2 upon receipt by the Company of such lawful consideration therefor as the Company's Board of Directors (or a duly authorized committee thereof) may determine, will constitute valid and binding obligations of the Company. 2. The shares of Common Stock being registered pursuant to the Registration Statement, when issued and delivered as contemplated by the Registration Statement and upon receipt by the Company of such lawful consideration therefor having a value not less than the par value thereof as the Company's Board of Directors (or a duly authorized committee thereof) may determine, will be validly issued, fully paid and nonassessable. 3. The shares of the Preferred Stock being registered pursuant to the Registration Statement, when issued and delivered as contemplated by the Registration Statement and upon receipt by the Company of such lawful consideration therefor having a value not less than the par value thereof as the Company's Board of Directors (or a duly authorized committee thereof) may determine, will be validly issued, fully paid and nonassessable. 4. The Depositary Shares being registered pursuant to the Registration Statement, when issued and delivered as contemplated by the Registration Statement and upon receipt by the Company of such lawful consideration therefor as the Company's Board of Directors (or a duly authorized committee thereof) may determine, will be validly issued, fully paid and nonassessable. 5. Any Warrants offered and sold as contemplated in the Registration Statement, when issued and sold in accordance with the resolutions of the Board of Directors authorizing the offer, issuance and sale of the Warrants, will be duly and validly authorized and will constitute valid and binding obligations of the Company. 6. The Stock Purchase Contracts being registered pursuant to the Registration Statement, when issued and delivered as contemplated by the Registration Statement and upon receipt by the Company of such lawful consideration therefor as the Company's Board of Directors (or a duly authorized committee thereof) may determine, will constitute valid and binding obligations of the Company. 7. The Stock Purchase Units being registered pursuant to the Registration Statement, when issued and delivered as contemplated by the Registration Statement and upon receipt by the Company of such lawful consideration therefor as the Company's Board of Directors (or a duly authorized committee thereof) may determine, will constitute valid and binding obligations of the Company. In rendering the foregoing opinions, we have assumed that: (i) the Registration Statement, and any amendments thereto, will have become effective; (ii) a Prospectus Supplement describing each class and/or series of Securities offered pursuant to the Parker-Hannifin Corporation February 14, 2002 Page 3 Registration Statement will have been filed with the Securities and Exchange Commission; (iii) the definitive terms of each class and/or series of Securities will have been established in accordance with the authorizing resolutions of the Company's Board of Directors, the Company's Articles of Incorporation and applicable law; (iv) any Securities, including Common Stock or Preferred Stock issuable upon conversion, exchange, or exercise of any other security, will have been duly authorized and reserved for issuance from the applicable class of capital stock of the Company, in each case within the limits of such class of capital stock then remaining authorized but unreserved and unissued; (v) the resolutions authorizing the Company to issue, offer and sell the Offered Securities will have been adopted by the Company's Board of Directors and will be in full force and effect at all times at which the Securities are offered or sold by the Company; and (vi) all Securities will be issued in compliance with applicable federal and state securities laws. With respect to any Securities consisting of any series of Debt Securities, we have further assumed that: (i) an Indenture with respect to such Debt Securities will have been duly executed and delivered by the Company and the applicable Trustee in a form approved by us, and such Indenture will have been qualified under the Trust Indenture Act of 1939, as amended; (ii) all terms of such Debt Securities not provided for in the applicable Indenture will have been established in accordance with the provision of the applicable Indenture and reflected in appropriate documentation approved by us and, if applicable, duly executed and delivered by the Company and the applicable Trustee; (iii) such Debt Securities will be duly executed, authenticated, issued and delivered in accordance with the provisions of the applicable Indenture; and (iv) the interest rate on any such Debt Securities will not be higher than the maximum lawful rate permitted from time to time under applicable law. In rendering the foregoing opinions, we have relied as to certain factual matters upon certificates of officers of the Company, and we have not independently checked or verified the accuracy of the statements contained therein. In rendering the foregoing opinions, our examination of matters of law has been limited to the laws of the State of Ohio, the laws of the State of New York, and the federal laws of the United States of America, as in effect on the date hereof. We understand that prior to offering for sale any Securities you will advise us in writing of the terms thereof, will afford us an opportunity to review the operative documents (including the applicable Prospectus Supplement) pursuant to which such Securities are to be offered and issued, and will file as an exhibit to the Registration Statement such supplement or amendment to this opinion (if any) as we may reasonably consider necessary or appropriate by reason of the terms of such Securities or any changes in the Company's capital structure or other pertinent circumstances. Parker-Hannifin Corporation February 14, 2002 Page 4 We hereby consent to the filing of this opinion as Exhibit 5 to the Registration Statement and to the reference to us under the caption "Legal Matters" in the Prospectus constituting a part of such Registration Statement. In giving such consent, we do not thereby admit that we are included in the category of persons whose consent is required under Section 7 of the Securities Act or the rules and regulations of the Securities and Exchange Commission promulgated thereunder. Very truly yours, /s/ Jones, Day, Reavis & Pogue Jones, Day, Reavis & Pogue