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                SIMPSON MANUFACTURING CO., INC. AND SUBSIDIARIES
                         CHANGE IN ACCOUNTING PRINCIPLE

                                   EXHIBIT 18


April 19, 2001

Board of Directors
Simpson Manufacturing Co., Inc.
4120 Dublin Boulevard, Suite 400
Dublin, CA  94568

Dear Directors:

We are providing this letter to you for inclusion as an exhibit to your Form
10-Q filing pursuant to Item 601 of Regulation S-K.

We have been provided a copy of the Company's Quarterly Report on Form 10-Q for
the period ended March 31, 2001. Note 3 therein describes a change in accounting
principle from LIFO inventory accounting method to FIFO inventory accounting
method. It should be understood that the preferability of one acceptable method
of accounting over another for inventory accounting has not been addressed in
any authoritative accounting literature, and in expressing our concurrence below
we have relied on management's determination that this change in accounting
principle is preferable. Based on our reading of management's stated reasons and
justification for this change in accounting principle in the Form 10-Q, and our
discussions with management as to their judgment about the relevant business
planning factors relating to the change, we concur with management that such
change represents, in the Company's circumstances, the adoption of a preferable
accounting principle in conformity with Accounting Principles Board Opinion No.
20.

We have not audited any financial statements of the Company as of any date or
for any period subsequent to December 31, 2000. Accordingly, our comments are
subject to change upon completion of an audit of the consolidated financial
statements covering the period of the accounting change.

Very truly yours,

/s/PricewaterhouseCoopers LLP

San Francisco, California