EXHIBIT 4.2



                                 [LETTERHEAD]



July 24, 1997


(415) 765-2614


Ms. Delight Saxton
Chief Financial Officer and 
Vice President of Administration
McGrath RentCorp
2500 Grant Avenue
San Lorenzo, CA 94580

Re:  Credit available (at Bank's discretion) pursuant to that certain 
$5,000,000.00 Optional Advance Facility Letter ("Facility Letter") from Union 
Bank of California, N.A., formerly The Bank of California, N.A. ("Bank") to 
McGrath RentCorp, a California corporation ("Borrower") dated October 16, 
1996, as extended by an extension letter dated June 27, 1997, and further 
evidenced by that certain Optional Advance Note dated October 16, 1996, 
executed by Borrower to the order of Bank, as extended by an extension letter 
dated June 27, 1997 ("Optional Advance Note").

Dear Ms. Saxton:

Pursuant to the Facility Letter the Bank expressed its general willingness to 
extend credit to the Borrower. Capitalized terms used herein shall have the 
meanings given them in the Facility Letter and Optional Advance Note.

Bank and Borrower mutually desire to amend the Facility Letter and the 
Optional Advance Note in certain respects, and hereby agree as follows:

     The date "June 30, 1997" which appears in the first unnumbered paragraph 
     of the Facility Letter, in the first unnumbered paragraph of the 
     Optional Advance Note, and in paragraph 2.b. of the Optional Advance 
     Note (as extended by the extension letter described above) is hereby 
     amended to "June 30, 1998".

     The second sentence of the first unnumbered paragraph of the Facility 
     Letter is hereby amended to read as follows: "The term 'Agreement' as 
     used herein shall mean the Credit Agreement dated as of July 10, 1997, 
     between Borrower, Bank, Bank of America, National Trust & Savings
     Association, and Fleet Bank, N.A., and shall include any amendments 
     thereto as are agreed to by Bank as set forth below."

     The following phrase in the first sentence of section (iii) of the 
     Facility Letter: "under Articles 6, 7, and 8 of the Agreement is 
     hereby deleted and replaced with the following: under Articles 6, 7, 8 
     and 11 of the Agreement (and including any definitions and related 
     provisions) of the Agreement."



Ms. Delight Saxton
7/24/97
Page 2

     The second and third sentences of section (iii) of the Facility Letter 
     are deleted and replaced with the following: "Delivery to Bank of the 
     financial statements and other documents pursuant to Section 7.3 of the 
     Agreement shall be deemed delivery thereof to Bank for the purposes of 
     this Facility."

     Section (b) of the first sentence of paragraph 5 of the Optional Advance 
     Note is amended to read as follows: "(b) the occurrence of an Event of 
     Default as defined in the Agreement, or."

     The following sentence is added at the end of paragraph 6 of the 
     Optional Advance Note: "The capitalized terms used but not defined in 
     this note shall have the meanings given them in such facility letter."

     The following sentence is deleted from paragraph 6 of the Optional 
     Advance Note: "This note incorporates any alternative dispute resolution 
     agreement previously, concurrently or hereafter executed between Debtor 
     and Bank". The following is added as a new final paragraph to the 
     Facility Letter:

          BORROWER AND BANK HEREBY WAIVE ANY RIGHT TO TRIAL BY JURY OF ANY 
          CLAIM, DEMAND, ACTION OR CAUSE OF ACTION ARISING UNDER THIS FACILITY
          LETTER, THE NOTE OR ANY OTHER LOAN DOCUMENT OR IN ANY WAY CONNECTED 
          WITH OR RELATED OR INCIDENTAL HERETO OR THERETO, IN EACH CASE WHETHER
          NOW EXISTING OR HEREAFTER ARISING, AND WHETHER SOUNDING IN CONTRACT 
          OR TORT OR OTHERWISE; AND ANY SUCH CLAIM, DEMAND ACTION OR CAUSE OF 
          ACTION SHALL BE DECIDED BY COURT TRIAL WITHOUT A JURY. BORROWER OR 
          BANK MAY FILE AN ORIGINAL COUNTERPART OR A COPY OF THIS PARAGRAPH 
          WITH ANY COURT AS WRITTEN EVIDENCE OF THIS CONSENT OF BORROWER AND 
          BANK TO WAIVE THEIR RIGHT TO TRIAL BY JURY.

Except as specifically provided herein, all terms and conditions of the 
Facility Letter and Optional Advance Note remain in full force and effect, 
without waiver or modification. Borrower hereby confirms all terms and 
conditions contained in the Facility Letter. Further, Borrower certifies 
that, as of the date of this letter, there exists neither (i) any material 
adverse change to Borrower, its business, the property, or to any guarantor, 
nor (ii) any material misrepresentation or omission in any of the information 
or materials submitted by Borrower to Bank in connection with the Facility, 
nor (iii) any condition, act or event which with the giving of notice or the 
passage of time or both would constitute a material adverse change, 
misrepresentation or omission.

BORROWER ACKNOWLEDGES THAT THE FACILITY IS NOT A COMMITTED FACILITY. IN ITS 
SOLE DISCRETION, FOR ANY REASON OR FOR NO REASON AND WITH OR WITHOUT NOTICE, 
BANK MAY DECLINE TO MAKE ANY OR ALL REQUESTED



Ms. Delight Saxton
7/24/97
Page 3

ADVANCES UNDER THE FACILITY, MAY DECLINE TO CONTINUE OR FURTHER RENEW THE 
FACILITY, AND MAY TERMINATE THE FACILITY AT ANY TIME.

Please indicate acceptance of the terms of this letter amendment by executing 
the enclosed copy and returning it to me no later than the Bank's close of 
business on July 25, 1997, at which time, unless the executed copy is 
received, the amendments contained herein shall expire.

Yours truly,

Union Bank of California, N.A.

By:  /s/ Robert John Vernagallo
   -------------------------------
       Robert John Vernagallo,
       Vice President


ACCEPTED AND AGREED:

MCGRATH RENTCORP, a
California corporation


By: /s/ Delight Saxton
   ---------------------------------

Title:  Vice President of Admin
      ------------------------------

By:  /s/ Thomas J. Sauer
   ---------------------------------

Title:  Vice President
      ------------------------------

Date:        July 29          , 1997
     -------------------------