EXHIBIT 28
 
                    REPORT OF INDEPENDENT PUBLIC ACCOUNTANTS
 
To Costco Companies, Inc.:
 
    We have reviewed the accompanying condensed consolidated balance sheet of
Costco Companies, Inc. (a Delaware corporation) and subsidiaries as of May 10,
1998, and the related condensed consolidated statements of income for the
twelve-week and thirty-six-week periods ended May 10, 1998 and May 11, 1997, and
the condensed consolidated statements of cash flows for the thirty-six-week
periods then ended. These financial statements are the responsibility of the
Company's management.
 
    We conducted our review in accordance with standards established by the
American Institute of Certified Public Accountants. A review of interim
financial information consists principally of applying analytical procedures to
financial data and making inquiries of persons responsible for financial and
accounting matters. It is substantially less in scope than an audit conducted in
accordance with generally accepted auditing standards, the objective of which is
the expression of an opinion regarding the financial statements taken as a
whole. Accordingly, we do not express such an opinion.
 
    Based on our review, we are not aware of any material modifications that
should be made to the financial statements referred to above for them to be in
conformity with generally accepted accounting principles.
 
                                          ARTHUR ANDERSEN LLP
 
Seattle, Washington
May 29, 1998
 
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