COSTCO WHOLESALE CORPORATION REPORTS FIRST QUARTER
    FISCAL 2000 OPERATING RESULTS AND ANNOUNCES UPCOMING 2-FOR-1 STOCK SPLIT


     ISSAQUAH,  Wash.,  December 9 3/4 Costco Wholesale Corporation ("Costco" or
the "Company") (Nasdaq:COST) announced today its operating results for the first
quarter of fiscal 2000, the 12 weeks ended November 21, 1999.

     Sales for the first  quarter of fiscal 2000  increased 16% to $6.82 billion
from $5.89  billion  during the first  quarter of fiscal  1999.  On a comparable
warehouse basis, that is warehouses open at least a year, net sales increased by
13%.

     Net income for the first quarter of fiscal 2000 was $129.3 million, or $.56
per diluted share. Excluding the impact of a one-time accounting charge taken in
last year's first  quarter,  net income for the first quarter of fiscal 1999 was
$104.2 million, or $.46 per diluted share, resulting in year-over-year  earnings
and earnings per share  increases of 24% and 22%,  respectively.  In last year's
first quarter,  the Company recorded a $118 million non-cash,  after-tax charge,
reflecting  the  cumulative  effect of the Company's  change in  accounting  for
membership fees from a cash to a deferred method,  whereby membership fee income
is recognized  ratably over the one-year life of the membership.  Including this
one-time charge,  the Company last year reported a loss of $13.8 million or $.05
per diluted share for the first quarter of fiscal 1999.

     The Company also  announced  today that its Board of  Directors  approved a
2-for-1  split of its common  stock.  Shareholders  will receive one  additional
share of common  stock for every share held on the record  date of December  24,
1999.  Additional  shares will be mailed or  delivered  on or about  January 13,
2000, by the Company's transfer agent,  ChaseMellon  Shareholder  Services.  The
common stock will begin trading at a post-split price on January 14, 2000.

     Costco  currently  operates  302  warehouses,  including  230 in the United
States, 59 in Canada, seven in the United Kingdom, three in Korea, two in Taiwan
and a warehouse in Japan. The Company also operates 17 warehouses in Mexico with
a joint  venture  partner.  The Company plans to open an additional 15 to 20 new
warehouses  (including four to six relocations of existing  warehouses to larger
and  better-located  facilities)  prior to the end of its  fiscal  year  2000 on
September 3, 2000.


         CONTACTS:           Costco Wholesale Corporation
                             Richard Galanti, 425/313-8203
                             Bob Nelson, 425/313-8255





                          COSTCO WHOLESALE CORPORATION

                   CONDENSED CONSOLIDATED STATEMENTS OF INCOME
                  (dollars in thousands, except per share data)
                                   (unaudited)



                                                                               12 Weeks Ended
                                                                     ------------------------------------
                                                                     November 21, 1999  November 22, 1998
                                                                     -----------------  -----------------
                                                                                  
REVENUE
Net sales.............................................................  $ 6,824,197     $  5,894,238
Membership fees and other.............................................      119,315          103,840
                                                                        -----------     ------------
 Total revenue........................................................    6,943,512        5,998,078

OPERATING EXPENSES
Merchandise costs.....................................................    6,120,201        5,287,785
Selling, general and administrative...................................      596,717          518,990
Preopening expenses...................................................       10,334           10,707
Provision for impaired assets and warehouse closing costs.............        1,000            2,000
                                                                        -----------     ------------
 Operating income.....................................................      215,260          178,596

OTHER INCOME (EXPENSE)
Interest expense......................................................      (10,397)         (10,912)
Interest income and other.............................................       10,667            6,039
                                                                        -----------     ------------
INCOME BEFORE INCOME TAXES AND CUMULATIVE
  EFFECT OF ACCOUNTING CHANGE.........................................      215,530          173,723
Provision for income taxes............................................       86,212           69,489
                                                                        -----------     ------------
INCOME BEFORE CUMULATIVE EFFECT OF
  ACCOUNTING CHANGE...................................................      129,318          104,234
Cumulative effect of accounting change, net of tax....................         --           (118,023)
                                                                        -----------     ------------
NET INCOME (LOSS).....................................................   $  129,318       $  (13,789)
                                                                        -----------     ------------
NET INCOME (LOSS) PER COMMON SHARE:
 Basic earnings per share:
  Income before cumulative effect of accounting change................   $      .58       $      .48
  Cumulative effect of accounting change, net of tax..................         --               (.54)
                                                                        -----------     ------------
  Net Income (loss)...................................................   $      .58       $     (.06)
                                                                        -----------     ------------
 Diluted earnings per share:
  Income before cumulative effect of accounting change................   $      .56       $      .46
  Cumulative effect of accounting change, net of tax..................         --               (.51)
                                                                        -----------     ------------
  Net Income (loss)...................................................   $      .56       $     (.05)
                                                                        -----------     ------------

Shares used in calculation (000's)
 Basic................................................................      221,650          217,838
 Diluted..............................................................      236,707          233,387