

                                                                       EXHIBIT 5


                            TELECOPIER (513) 579-6956


                                   May 7, 1999



Direct Dial:  (513) 579-6560



Cintas Corporation
6800 Cintas Boulevard
Cincinnati, Ohio  45262

Gentlemen:

     We serve as your  General  Counsel and are familiar  with your  Articles of
Incorporation, By-laws and corporate proceedings. On this basis, we have made an
examination as to:

     1.   The organization of Cintas Corporation;

     2.   The legal sufficiency of all corporate  proceedings of the Corporation
in connection with the authorization  and issuance of all presently  outstanding
and issued Common Stock of the Corporation; and

     3.   The legal sufficiency of all corporate proceedings taken in connection
with the authorization of the issuance of 7,500,000 shares of Common Stock to be
included in a Registration Statement on Form S-4 to be filed with the Securities
and Exchange Commission.

     Based upon such examination, we are of the opinion that:


     1.    Cintas   Corporation  is  a  duly  organized  and  validly   existing
corporation under the laws of the State of Washington;

     2.   Cintas  Corporation  has taken all  necessary  and required  corporate
actions in  connection  with the  issuance of  7,500,000  shares of newly issued
Common  Stock and the  aforesaid  7,500,000  shares of Common  Stock are validly
authorized,  legally issued, fully paid and nonassessable shares of Common Stock
of the Corporation free of any preemptive rights.



<PAGE>



Cintas Corporation
Page 2
May 7, 1999


     We hereby consent to be named in the aforesaid  Registration  Statement and
the Prospectus part thereof as the attorneys who will pass upon legal matters in
connection with the issuance of the aforesaid  Common Stock and to the filing of
this opinion as an exhibit to the Registration Statement and furthermore consent
to references made to this firm in the Registration Statement.

                                      Very truly yours,

                                      KEATING, MUETHING & KLEKAMP, P.L.L.


                                      BY: /s/ Robert E. Coletti       
                                         --------------------------------
                                              Robert E. Coletti



