<PAGE>   1

--------------------------------------------------------------------------------
--------------------------------------------------------------------------------

                       SECURITIES AND EXCHANGE COMMISSION
                             WASHINGTON, D.C. 20549
                            ------------------------

                                   FORM 10-Q

(MARK ONE)

[X]  QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE
     SECURITIES EXCHANGE ACT OF 1934

                 FOR THE QUARTERLY PERIOD ENDED AUGUST 1, 1999

                                       OR

[ ]   TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE
     SECURITIES EXCHANGE ACT OF 1934

                  FOR THE TRANSITION PERIOD FROM           TO

                        COMMISSION FILE NUMBER 001-13927

                              CSK AUTO CORPORATION
             (EXACT NAME OF REGISTRANT AS SPECIFIED IN ITS CHARTER)

<TABLE>
<S>                                                            <C>
                         DELAWARE                                                   86-0765798
              (STATE OR OTHER JURISDICTION OF                                    (I.R.S. EMPLOYER
              INCORPORATION OR ORGANIZATION)                                    IDENTIFICATION NO.)
     645 E. MISSOURI AVE. SUITE 400, PHOENIX, ARIZONA                                  85012
         (ADDRESS OF PRINCIPAL EXECUTIVE OFFICES)                                   (ZIP CODE)
</TABLE>

                                 (602) 265-9200
              (REGISTRANT'S TELEPHONE NUMBER, INCLUDING AREA CODE)

                                      N/A
              (FORMER NAME, FORMER ADDRESS AND FORMER FISCAL YEAR,
                         IF CHANGED SINCE LAST REPORTS)

     Indicate by check mark whether the registrant (1) has filed all reports
required to be filed by Section 13 or 15(d) of the Securities Exchange Act of
1934 during the preceding 12 months (or for such shorter period that the
registrant was required to file such reports), and (2) has been subject to such
filing requirements for the past 90 days.

                          Yes [X]               No [ ]

     As of September 7, 1999, CSK Auto Corporation had 27,826,114 shares of
common stock outstanding.

--------------------------------------------------------------------------------
--------------------------------------------------------------------------------
<PAGE>   2

                                     PART I

                             FINANCIAL INFORMATION

ITEM 1.  FINANCIAL STATEMENTS

                      CSK AUTO CORPORATION AND SUBSIDIARY
                          CONSOLIDATED BALANCE SHEETS
                       (IN THOUSANDS, EXCEPT SHARE DATA)

<TABLE>
<CAPTION>
                                                               AUGUST 1,     JANUARY 31,
                                                                 1999           1999
                                                              -----------    -----------
                                                              (UNAUDITED)
<S>                                                           <C>            <C>
ASSETS
Cash and cash equivalents...................................   $   6,625      $   7,490
Receivables, net of allowances of $1,879 and $1,703,
  respectively..............................................      57,333         58,867
Inventories.................................................     482,540        414,422
Assets held for sale........................................       3,444          5,018
Prepaid expenses and other current assets...................      21,934         18,295
                                                               ---------      ---------
          Total current assets..............................     571,876        504,092
                                                               ---------      ---------
Property and equipment, net.................................     119,270        105,037
Leasehold interests, net....................................       9,138          9,643
Deferred income taxes.......................................       6,370         10,695
Goodwill, net...............................................      54,231             --
Other assets, net...........................................      10,010          7,209
                                                               ---------      ---------
          Total assets......................................   $ 770,895      $ 636,676
                                                               =========      =========
LIABILITIES AND STOCKHOLDERS' EQUITY
Accounts payable............................................   $ 129,763      $ 122,304
Accrued payroll and related expenses........................      24,945         25,962
Accrued expenses and other current liabilities..............      37,777         35,312
Current maturities of amounts due under Senior Credit
  Facility..................................................       1,840            840
Current maturities of capital lease obligations.............       7,691          8,749
Deferred income taxes.......................................       4,046          4,046
                                                               ---------      ---------
          Total current liabilities.........................     206,062        197,213
                                                               ---------      ---------
Amounts due under Senior Credit Facility....................     325,900        224,320
Obligations under 11% Senior Subordinated Notes.............      81,250         81,250
Obligations under capital leases............................      18,802         18,134
Other.......................................................      10,136         10,370
                                                               ---------      ---------
          Total non-current liabilities.....................     436,088        334,074
                                                               ---------      ---------
Commitments and contingencies
Stockholders' equity:
  Common stock, $0.01 par value, 50,000,000 shares
     authorized;
     27,824,619 and 27,768,832 shares issued and outstanding
     at
     August 1, 1999 and January 31, 1999, respectively......         278            278
  Additional paid-in capital................................     290,875        289,820
  Stockholder receivable....................................        (615)        (1,018)
  Deferred compensation.....................................        (409)          (493)
  Accumulated deficit.......................................    (161,384)      (183,198)
                                                               ---------      ---------
          Total stockholders' equity........................     128,745        105,389
                                                               ---------      ---------
          Total liabilities and stockholders' equity........   $ 770,895      $ 636,676
                                                               =========      =========
</TABLE>

  The accompanying notes are an integral part of these consolidated financial
                                  statements.
                                        1
<PAGE>   3

                      CSK AUTO CORPORATION AND SUBSIDIARY
                     CONSOLIDATED STATEMENTS OF OPERATIONS
                                  (UNAUDITED)
                (IN THOUSANDS, EXCEPT SHARE AND PER SHARE DATA)

<TABLE>
<CAPTION>
                                                    THIRTEEN WEEKS ENDED       TWENTY-SIX WEEKS ENDED
                                                  -------------------------   -------------------------
                                                   AUGUST 1,     AUGUST 2,     AUGUST 1,     AUGUST 2,
                                                     1999          1998          1999          1998
                                                  -----------   -----------   -----------   -----------
<S>                                               <C>           <C>           <C>           <C>
Net sales.......................................  $   302,322   $   254,701   $   571,724   $   493,124
Cost of sales...................................      159,593       137,040       298,844       267,746
                                                  -----------   -----------   -----------   -----------
Gross profit....................................      142,729       117,661       272,880       225,378
Other costs and expenses:
  Operating and administrative..................      113,329        95,422       220,257       188,445
  Transition and integration expenses...........          619            --           619         3,075
  Write-off of unamortized management fee.......           --            --            --         3,643
                                                  -----------   -----------   -----------   -----------
Operating profit................................       28,781        22,239        52,004        30,215
Interest expense, net...........................        8,143         7,410        15,492        16,608
                                                  -----------   -----------   -----------   -----------
Income before income taxes, extraordinary loss
  and cumulative effect of change in accounting
  principle.....................................       20,638        14,829        36,512        13,607
Income tax expense..............................        7,945         5,487        13,957         5,017
                                                  -----------   -----------   -----------   -----------
Income before extraordinary loss and cumulative
  effect of change in accounting principle......       12,693         9,342        22,555         8,590
Extraordinary loss, net of $4,236 of
  income taxes..................................           --            --            --        (6,767)
                                                  -----------   -----------   -----------   -----------
Income before cumulative effect of change in
  accounting principle..........................       12,693         9,342        22,555         1,823
Cumulative effect of change in accounting
  principle, net of $468 of income taxes........           --            --          (741)           --
                                                  -----------   -----------   -----------   -----------
Net income......................................  $    12,693   $     9,342   $    21,814   $     1,823
                                                  ===========   ===========   ===========   ===========
Basic earnings (loss) per share:
  Income before extraordinary loss and
     cumulative effect of change in accounting
     principle..................................  $      0.46   $      0.34   $      0.81   $      0.33
  Extraordinary loss, net of income taxes.......           --            --            --         (0.26)
                                                  -----------   -----------   -----------   -----------
  Income before cumulative effect of change in
     accounting principle.......................         0.46          0.34          0.81          0.07
  Cumulative effect of change in accounting
     principle, net of income taxes.............           --            --         (0.03)           --
                                                  -----------   -----------   -----------   -----------
  Net income....................................  $      0.46   $      0.34   $      0.78   $      0.07
                                                  ===========   ===========   ===========   ===========
  Shares used in computing per share amounts....   27,814,773    27,738,388    27,800,049    25,653,223
                                                  ===========   ===========   ===========   ===========
Diluted earnings (loss) per share:
  Income before extraordinary loss and
     cumulative effect of change in accounting
     principle..................................  $      0.44   $      0.33   $      0.78   $      0.32
  Extraordinary loss, net of income taxes.......           --            --            --         (0.25)
                                                  -----------   -----------   -----------   -----------
  Income before cumulative effect of change in
     accounting principle.......................         0.44          0.33          0.78          0.07
  Cumulative effect of change in accounting
     principle, net of income taxes.............           --            --         (0.02)           --
                                                  -----------   -----------   -----------   -----------
  Net income....................................  $      0.44   $      0.33   $      0.76   $      0.07
                                                  ===========   ===========   ===========   ===========
  Shares used in computing per share amounts....   28,673,234    28,662,448    28,804,643    26,578,154
                                                  ===========   ===========   ===========   ===========
</TABLE>

  The accompanying notes are an integral part of these consolidated financial
                                  statements.
                                        2
<PAGE>   4

                      CSK AUTO CORPORATION AND SUBSIDIARY
                CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY
                       (IN THOUSANDS, EXCEPT SHARE DATA)

<TABLE>
<CAPTION>
                                      COMMON STOCK      ADDITIONAL
                                   ------------------    PAID-IN     STOCKHOLDER     DEFERRED     ACCUMULATED    TOTAL
                                     SHARES    AMOUNT    CAPITAL     RECEIVABLE    COMPENSATION     DEFICIT      EQUITY
                                   ----------  ------   ----------   -----------   ------------   -----------   --------
<S>                                <C>         <C>      <C>          <C>           <C>            <C>           <C>
Balances at January 31, 1999.....  27,768,832   $278     $289,820      $(1,018)       $(493)       $(183,198)   $105,389
Amortization of deferred
  compensation (unaudited).......          --     --           --           --           84               --          84
Recovery of stockholder
  receivable (unaudited).........          --     --           --          403           --               --         403
Exercise of options
  (unaudited)....................      55,787     --          671           --           --               --         671
Tax benefit relating to stock
  option exercises (unaudited)...          --     --          384           --           --               --         384
Net income (unaudited)...........          --     --           --           --           --           21,814      21,814
                                   ----------   ----     --------      -------        -----        ---------    --------
Balances at August 1, 1999
  (unaudited)....................  27,824,619   $278     $290,875      $  (615)       $(409)       $(161,384)   $128,745
                                   ==========   ====     ========      =======        =====        =========    ========
</TABLE>

  The accompanying notes are an integral part of these consolidated financial
                                  statements.
                                        3
<PAGE>   5

                      CSK AUTO CORPORATION AND SUBSIDIARY
                     CONSOLIDATED STATEMENTS OF CASH FLOWS
                                  (UNAUDITED)
                                 (IN THOUSANDS)

<TABLE>
<CAPTION>
                                                               TWENTY-SIX WEEKS ENDED
                                                              ------------------------
                                                              AUGUST 1,     AUGUST 2,
                                                                 1999          1998
                                                              ----------    ----------
<S>                                                           <C>           <C>
Cash flows provided by (used in) operating activities:
  Net income................................................  $  21,814      $  1,823
  Adjustments to reconcile net income to net cash provided
     by (used in) operating activities:
     Depreciation and amortization of property and
      equipment.............................................     11,432        10,552
     Amortization of goodwill...............................        283            --
     Amortization of leasehold interests....................        400           475
     Amortization of other deferred charges.................        217           360
     Amortization of deferred financing costs...............        505           539
     Tax benefit relating to stock option exercises.........        384            --
     Extraordinary loss on early retirement of debt, net of
      income taxes..........................................         --         6,767
     Cumulative effect of change in accounting principle,
      net of income taxes...................................        741            --
     Write-off of unamortized management fee................         --         3,643
     Deferred income taxes..................................      4,793         5,017
     Change in operating assets and liabilities, net of
      effects of acquisition:
       Receivables..........................................      1,822        (3,854)
       Inventories..........................................    (48,056)       (1,168)
       Prepaid expenses and other current assets............     (1,543)       (2,881)
       Accounts payable.....................................     (5,486)        2,726
       Accrued payroll, accrued expenses and other current
        liabilities.........................................         28        (2,990)
     Other operating activities.............................     (2,890)       (4,303)
                                                              ---------      --------
     Net cash provided by (used in) operating activities....    (15,556)       16,706
                                                              ---------      --------
Cash flows provided by (used in) investing activities:
  Store acquisition, net of cash acquired...................    (62,063)           --
  Capital expenditures......................................    (19,924)      (18,640)
  Expenditures for assets held for sale.....................     (2,582)      (12,156)
  Proceeds from sale of property and equipment and assets
     held for sale..........................................      2,488        14,910
  Due to affiliate..........................................         --        (1,000)
  Other investing activities................................        (30)         (139)
                                                              ---------      --------
     Net cash used in investing activities..................    (82,111)      (17,025)
                                                              ---------      --------
Cash flows provided by (used in) financing activities:
  Borrowings under Senior Credit Facility...................    242,000        65,000
  Payments under Senior Credit Facility.....................   (139,420)      (63,645)
  Issuance of common stock in initial public offering.......         --       172,482
  Underwriter's discount and other IPO costs................         --       (13,771)
  Premiums paid upon early retirement of debt...............         --        (4,875)
  Retirement of 11% Senior Subordinated Notes...............         --       (43,750)
  Retirement of 12% Subordinated Notes......................         --       (50,000)
  Payment of Senior Credit Facility with public offering
     proceeds...............................................         --       (53,825)
  Payment of debt issuance costs............................     (1,646)           --
  Payments on capital lease obligations.....................     (4,774)       (4,472)
  Recovery of stockholder receivable........................        403           150
  Exercise of options.......................................        671            --
  Other financing activities................................       (432)         (249)
                                                              ---------      --------
     Net cash provided by financing activities..............     96,802         3,045
                                                              ---------      --------
     Net increase (decrease) in cash and cash equivalents...       (865)        2,726
Cash and cash equivalents, beginning of period..............      7,490         4,852
                                                              ---------      --------
Cash and cash equivalents, end of period....................  $   6,625      $  7,578
                                                              =========      ========
</TABLE>

  The accompanying notes are an integral part of these consolidated financial
                                  statements.
                                        4
<PAGE>   6

                      CSK AUTO CORPORATION AND SUBSIDIARY
                   NOTES TO CONSOLIDATED FINANCIAL STATEMENTS
               THIRTEEN AND TWENTY-SIX WEEKS ENDED AUGUST 1, 1999

     CSK Auto Corporation is a holding company. At August 1, 1999, CSK Auto
Corporation had no business activity other than its investment in CSK Auto,
Inc., a wholly-owned subsidiary ("Auto"). On a consolidated basis, CSK Auto
Corporation and Auto are referred to herein as the "Company."

     Auto is a specialty retailer of automotive aftermarket parts and
accessories. At August 1, 1999, the Company operated 926 stores in 17 Western
and Northern Plains states as a fully integrated company under four brand names:
Checker Auto Parts, founded in 1969 and operating in the Southwestern and Rocky
Mountain states; Schuck's Auto Supply, founded in 1917 and operating in the
Pacific Northwest; Kragen Auto Parts, founded in 1947 and operating primarily in
California; and Big Wheel/Rossi, founded in 1944 and operating in the Northern
Plains.

NOTE 1 -- BASIS OF PRESENTATION

     The unaudited consolidated financial statements included herein were
prepared by the Company pursuant to the rules and regulations of the Securities
and Exchange Commission, but do not include all information and footnotes
required by generally accepted accounting principles. In the opinion of
management, the condensed consolidated financial statements reflect all
adjustments, which are of a normal recurring nature, necessary for a fair
presentation of the Company's financial position and the results of its
operations and cash flows. The accompanying consolidated financial statements
should be read in conjunction with the consolidated financial statements and
related notes thereto for the fiscal year ended January 31, 1999, as included in
the Company's Annual Report on Form 10-K filed on April 28, 1999.

NOTE 2 -- INVENTORIES

     Inventories are valued at the lower of cost or market, cost being
determined utilizing the last-in, first-out (LIFO) method. An actual valuation
of inventory under the LIFO method can only be calculated at the end of a fiscal
year based upon the inventory levels and costs at that time. Accordingly,
interim LIFO calculations reflected herein are based upon management's estimates
of year-end inventory levels and costs. The replacement cost of inventories
approximated $421.9 million and $356.7 million at August 1, 1999 and January 31,
1999, respectively.

NOTE 3 -- EARNINGS PER SHARE

     Calculation of shares used in computing per share amounts is summarized as
follows (unaudited):

<TABLE>
<CAPTION>
                                                    THIRTEEN WEEKS ENDED     TWENTY-SIX WEEKS ENDED
                                                   -----------------------   -----------------------
                                                   AUGUST 1,    AUGUST 2,    AUGUST 1,    AUGUST 2,
                                                      1999         1998         1999         1998
                                                   ----------   ----------   ----------   ----------
<S>                                                <C>          <C>          <C>          <C>
  Common stock outstanding:
     Beginning of period.........................  27,805,466   27,738,388   27,768,832   19,113,388
                                                   ==========   ==========   ==========   ==========
     End of period...............................  27,824,619   27,738,388   27,824,619   27,738,388
                                                   ==========   ==========   ==========   ==========
  Issued during the period.......................      19,153           --       55,787    8,625,000
                                                   ==========   ==========   ==========   ==========
  Weighted average number of shares (Basic)......  27,814,773   27,738,388   27,800,049   25,653,223
  Effects of dilutive securities.................     858,461      924,060    1,004,594      924,931
                                                   ----------   ----------   ----------   ----------
  Weighted average number of shares (Dilutive)...  28,673,234   28,662,448   28,804,643   26,578,154
                                                   ==========   ==========   ==========   ==========
</TABLE>

NOTE 4 -- RECENT ACCOUNTING PRONOUNCEMENTS AND CUMULATIVE EFFECT OF CHANGE IN
          ACCOUNTING PRINCIPLE

     In March 1998, the Accounting Standards Executive Committee of the American
Institute of Certified Public Accountants issued Statement of Position ("SOP")
98-1, "Accounting for the Cost of Computer Software Developed or Obtained for
Internal Use." The SOP defines the characteristics of internal-use computer
software, the criteria for capitalization and financial statement disclosure
requirements. The SOP is effective for fiscal years
                                        5
<PAGE>   7
                      CSK AUTO CORPORATION AND SUBSIDIARY
           NOTES TO CONSOLIDATED FINANCIAL STATEMENTS -- (CONTINUED)
               THIRTEEN AND TWENTY-SIX WEEKS ENDED AUGUST 1, 1999

beginning after December 15, 1998, with earlier application encouraged. The
Company adopted SOP 98-1 in the first quarter of fiscal 1999 and such adoption
did not have a material effect on the Company's financial condition or results
of operations.

     In April 1998, the Accounting Standards Executive Committee of the American
Institute of Certified Public Accountants issued SOP 98-5, "Reporting on the
Cost of Start-up Activities." The SOP broadly defines start-up activities as
those one-time activities related to opening a new facility, introducing a new
product or service, conducting business in a new territory, or commencing some
new operation. The SOP requires that the costs of start-up activities be
expensed as incurred and is effective for financial statements for fiscal years
beginning after December 15, 1998, with earlier application encouraged. The
Company's historical accounting policy with respect to the cost of start-up
activities (store preopening expenses) was to defer such costs for the
approximately three month period of time that it takes to develop a new store
facility and to expense such costs during the month that the new store opens.
The Company adopted SOP 98-5 in the first quarter of fiscal 1999, which required
the Company to change its accounting policy to expense start-up costs as
incurred. Upon adoption, the Company expensed approximately $741,000, net of an
income tax benefit of $468,000, of preopening expenses that had been deferred as
of January 31, 1999. Such expense is reflected in the accompanying consolidated
statement of operations as the cumulative effect of a change in accounting
principle.

NOTE 5 -- BIG WHEEL ACQUISITION

     On June 30, 1999, the Company acquired substantially all of the assets of
Apsco Products Company dba Big Wheel/Rossi ("Big Wheel"), the leading retailer
of auto parts in the Northern Plains states. Big Wheel operated 86 stores in
Minnesota, North Dakota and Wisconsin along with a distribution center in
Minnesota. The Company is in the process of converting these stores to the
Checker name and store format and integrating these stores into the Company's
operations.

     The Company paid approximately $62.1 million in cash for substantially all
the assets and assumed certain current liabilities and indebtedness of Big
Wheel. The acquisition was funded with proceeds from the Senior Credit Facility.
In connection with the acquisition, the Company amended and restated the Senior
Credit Facility to provide an additional $125.0 million of senior term loan
borrowing ability.

     In connection with the integration of the Big Wheel stores, the Company
will incur one-time transition and integration expenses estimated to be $7.0
million, consisting primarily of grand opening advertising, training and re-
merchandising costs. Approximately $0.6 million of such expenses were incurred
during the second quarter of fiscal 1999 with the balance expected to be
incurred during the third and fourth quarters of fiscal 1999. In addition, the
Company will incur one-time capital expenditures of approximately $6.0 million,
consisting primarily of expenditures related to equipment, store fixtures,
signage and the installation of the Company's store-level information systems in
the Big Wheel stores. All of such capital expenditures are expected to be
incurred during the third and fourth quarters of fiscal 1999.

     The Big Wheel acquisition was accounted for under the purchase method of
accounting. Accordingly, the results of operations of these stores are included
in the consolidated operating results of the Company from July 1, 1999, the
first day of operations subsequent to the acquisition, and were not material.

NOTE 6 -- LEGAL MATTERS

     The Company was served with a lawsuit that was filed in the Superior Court
in San Diego, California on May 4, 1998. The case is brought by two former store
managers and a former senior assistant manager. It purports to be a class action
for all present and former California store managers and senior assistant
managers and seeks overtime pay for a period beginning in May 1995 as well as
injunctive relief requiring overtime pay in the future. The Company was also
served with two other lawsuits purporting to be class actions filed in
California state courts in Orange and Fresno Counties by thirteen other former
and current employees. These lawsuits include similar claims
                                        6
<PAGE>   8
                      CSK AUTO CORPORATION AND SUBSIDIARY
           NOTES TO CONSOLIDATED FINANCIAL STATEMENTS -- (CONTINUED)
               THIRTEEN AND TWENTY-SIX WEEKS ENDED AUGUST 1, 1999

to the San Diego lawsuit, except that they also include claims for unfair
business practices which seek overtime from October 1994. The Orange County
lawsuit initially included claims for punitive damages and unlawful conversion,
but the Court subsequently dismissed both of these claims. The three cases have
recently been "coordinated" before one judge in San Diego County and discovery
is being conducted by the parties. If these cases are permitted by the courts to
proceed as a class action and are decided against the Company, the aggregate
potential exposure could be material to results of operations or cash flows for
the year in which the cases are ultimately decided. The Company does not
believe, however, that such an adverse outcome, if it were to happen, would
materially affect the Company's financial position, operations or cash flows in
subsequent periods. Although at this stage in the litigation it is difficult to
predict its outcome with any certainty, the Company believes that there are
meritorious defenses to all of these cases and intends to defend them
vigorously.

     The Company currently and from time to time is involved in other litigation
incidental to the conduct of business. The damages claimed in some of these
litigations are substantial. Although the amount of liability that may result
from these matters cannot be ascertained, the Company does not currently believe
that, in the aggregate, they will result in liabilities material to its
consolidated financial condition, results of operations or cash flows.

NOTE 7 -- SUBSEQUENT EVENTS

     On August 20, 1999, the Company entered into a definitive agreement with
PACCAR Inc. to acquire PACCAR's wholly-owned subsidiary which operates 192
stores under the trade names of Grand Auto Supply and Al's Auto Supply in
Washington, California, Idaho, Oregon, Nevada and Alaska. Based on the
agreement, the Company will pay approximately $143.2 million in cash for the
stock of PACCAR's subsidiary. The Company plans to fund the purchase through its
Senior Credit Facility, which will be increased. The transaction is expected to
close in October 1999.

     On August 16, 1999, the Company entered into a definitive agreement to
purchase Automotive Information Systems ("AIS"). AIS, based in St. Paul,
Minnesota, is a leading provider of diagnostic vehicle repair information to
automotive technicians, automotive replacement parts manufacturers, automotive
test equipment manufacturers and the Do-It-Yourself consumer. The Company paid
approximately $10 million in cash for AIS and funded the acquisition through its
Senior Credit Facility. The transaction closed on September 7, 1999.

                                        7
<PAGE>   9

ITEM 2.  MANAGEMENT'S DISCUSSION AND ANALYSIS OF FINANCIAL CONDITION AND RESULTS
OF OPERATIONS

OVERVIEW

     Our business is somewhat seasonal in nature, with the highest sales
occurring in the summer months of June through August (overlapping our second
and third fiscal quarters). Our business is, in addition, affected by weather
conditions. While unusually severe or inclement weather tends to reduce sales as
our customers tend to defer elective maintenance during such periods, extremely
hot and cold temperatures tend to enhance sales by causing auto parts to fail
and sales of seasonal products to increase.

RESULTS OF OPERATIONS

     The following table expresses the statements of operations as a percentage
of sales for the periods shown:

<TABLE>
<CAPTION>
                                                           THIRTEEN WEEKS ENDED     TWENTY-SIX WEEKS ENDED
                                                          ----------------------    -----------------------
                                                          AUGUST 1,    AUGUST 2,    AUGUST 1,     AUGUST 2,
                                                            1999         1998         1999          1998
                                                          ---------    ---------    ---------     ---------
<S>                                                       <C>          <C>          <C>           <C>
Net sales...............................................    100.0%       100.0%       100.0%        100.0%
Cost of sales...........................................     52.8         53.8         52.3          54.3
                                                            -----        -----        -----         -----
Gross profit............................................     47.2         46.2         47.7          45.7
Operating and administrative............................     37.5         37.5         38.5          38.2
Transition and integration expenses.....................      0.2           --          0.1           0.6
Write-off of unamortized management fee.................       --           --           --           0.7
                                                            -----        -----        -----         -----
Operating profit........................................      9.5          8.7          9.1           6.2
Interest expense, net...................................      2.7          2.9          2.7           3.4
                                                            -----        -----        -----         -----
Income before income taxes, extraordinary loss and
  cumulative effect of change in accounting principle...      6.8          5.8          6.4           2.8
Income tax expense......................................      2.6          2.2          2.5           1.0
                                                            -----        -----        -----         -----
Income before extraordinary loss and cumulative effect
  of change in accounting principle.....................      4.2          3.6          3.9           1.8
Extraordinary loss, net of income taxes.................       --           --           --          (1.4)
                                                            -----        -----        -----         -----
Income before cumulative effect of change in accounting
  principle.............................................      4.2          3.6          3.9           0.4
Cumulative effect of change in accounting principle, net
  of income taxes.......................................       --           --         (0.1)           --
                                                            -----        -----        -----         -----
Net income..............................................      4.2%         3.6%         3.8%          0.4%
                                                            =====        =====        =====         =====
</TABLE>

  Thirteen Weeks Ended August 1, 1999 Compared to Thirteen Weeks Ended August 2,
1998

     Net sales for the thirteen weeks ended August 1, 1999 (the "second quarter
of fiscal 1999") increased $47.6 million, or 18.7%, over net sales for the
thirteen week period ended August 2, 1998 (the "second quarter of fiscal 1998").
This increase reflects both a comparable store sales increase of 6% and an
increase in the number of stores operated. During the second quarter of fiscal
1999, we acquired 86 former Big Wheel/Rossi stores ("Big Wheel") from Apsco
Products Company, which stores produced $7.5 million in net sales during the
portion of the quarter that we owned them. In addition to the Big Wheel stores,
during the second quarter of fiscal 1999 we opened 18 new stores, relocated 6
stores and expanded 3 stores. At August 1, 1999, we had 926 stores in operation
compared to 747 stores at the end of the second quarter of fiscal 1998.

     Gross profit for the second quarter of fiscal 1999 was $142.7 million, or
47.2% of net sales, compared to $117.7 million, or 46.2% of net sales, for the
comparable period of fiscal 1998. The increase in gross profit percentage
primarily resulted from our ability to obtain generally better pricing and more
favorable terms and support from our vendors due to increased purchase volume,
improved financial performance and stronger capitalization.

                                        8
<PAGE>   10

     Operating and administrative expenses increased by $17.9 million to $113.3
million, or 37.5% of net sales, for the second quarter of fiscal 1999 from $95.4
million, or 37.5% of net sales, for the comparable period of fiscal 1998. The
dollar increase is primarily the result of the operating costs of new stores.

     Operating profit increased to $28.8 million, or 9.5% of net sales, for the
second quarter of fiscal 1999 compared to $22.2 million or 8.7% of net sales for
the comparable period of fiscal 1998, due to the factors cited above. In
addition, the current period operating profit includes $0.6 million of expense
associated with the integration of the Big Wheel stores into our operations.

     Interest expense for the second quarter of fiscal 1999 totaled $8.1 million
compared to $7.4 million for the second quarter of fiscal 1998. The expense
increased primarily as a result of the additional indebtedness incurred to fund
the Big Wheel acquisition in the second quarter of 1999.

     Income tax expense for the second quarter of fiscal 1999 was $7.9 million
compared to an income tax expense of $5.5 million for the comparable period of
fiscal 1998. Our effective tax rate increased during the 1999 period to
approximately 38.5% of pre-tax income from approximately 37.0% in the comparable
1998 period as a result of certain tax credits that were realized in the prior
year which were not available in the current year.

     As a result of the above factors, net income increased to $12.7 million, or
$0.44 per diluted common share, for the second quarter of fiscal 1999, compared
to a net income of $9.3 million, or $0.33 per diluted common share, for the
second quarter of fiscal 1998.

  Twenty-six Weeks Ended August 1, 1999 Compared to Twenty-six Weeks Ended
August 2, 1998

     Net sales for the twenty-six weeks ended August 1, 1999 (the "first half of
fiscal 1999"), increased $78.6 million, or 15.9%, over net sales for the
twenty-six week period ended August 2, 1998 (the "first half of fiscal 1998").
This increase reflects both a comparable store sales increase of 5% and an
increase in the number of stores operated. During the second quarter of fiscal
1999, we acquired 86 former Big Wheel stores, which produced $7.5 million in net
sales during the portion of the fiscal year that we owned them. In addition to
the Big Wheel stores, during the first half of fiscal 1999 we opened 35 new
stores, relocated 11 stores, expanded 7 stores, acquired 2 stores and closed 4
stores in addition to those closed due to relocation. At August 1, 1999, we had
926 stores in operation compared to 747 stores at the end of the first half of
fiscal 1998.

     Gross profit for the first half of fiscal 1999 was $272.9 million, or 47.7%
of net sales, compared to $225.4 million, or 45.7% of net sales, for the
comparable period of fiscal 1998. The increase in gross profit percentage
primarily resulted from our ability to obtain generally better pricing and more
favorable terms and support from our vendors due to increased purchase volume,
improved financial performance and stronger capitalization.

     Operating and administrative expenses increased by $31.8 million to $220.3
million, or 38.5% of net sales, for the first half of fiscal 1999 from $188.4
million, or 38.2% of net sales, for the comparable period of fiscal 1998. The
increase is primarily the result of the operating costs of new stores.

     Operating profit increased to $52.0 million, or 9.1% of net sales, for the
first half of fiscal 1999 from $30.2 million, or 6.2% of net sales for the
comparable period of fiscal 1998, due to the factors cited above. During the
first quarter of fiscal 1998, we incurred $3.1 million of expenses associated
with the integration of the stores acquired in December 1997 from Trak Auto
Corporation and a $3.6 million non-recurring charge associated with the
termination of a management agreement as a result of our initial public offering
("IPO").

     Interest expense for the first half of fiscal 1999 totaled $15.5 million
compared to $16.6 million for the comparable period of fiscal 1998. Interest
expense decreased as a result of the reduction of debt in the 1998 period
relating of the early retirement of approximately $147.6 million of outstanding
debt with the proceeds of our IPO. However, this was offset by the additional
borrowings used to fund the Big Wheel acquisition in the second quarter of 1999.
In addition, generally lower interest rates were paid during fiscal 1999 on our
variable rate debt. The retirement of the debt in fiscal 1998 also produced an
extraordinary loss of $6.8 million, net of income tax, which consisted primarily
of prepayment premiums paid in connection with the redemption of debt and the
write-off of a portion of deferred debt issuance costs.

                                        9
<PAGE>   11

     Income tax expense for the first half of fiscal 1999 was $14.0 million
compared to an income tax expense of $5.0 million for the comparable 1998
period. Our effective tax rate increased during the 1999 period to approximately
38.2% of pre-tax income from approximately 36.9% in the comparable 1998 period
as a result of certain tax credits that were realized in the prior year which
were not available in the current year.

     The first half of fiscal 1999 was affected by a charge of $0.7 million, net
of income tax, relating to the cumulative effect of a change in accounting
principle associated with the adoption of SOP 98-5. See Note 4 to the
Consolidated Financial Statements.

     As a result of the above factors, net income increased to $21.8 million, or
$0.76 per diluted common share, for the first half of fiscal 1999, compared to a
net income of $1.8 million, or $0.07 per diluted common share, for the
comparable period of fiscal 1998.

LIQUIDITY AND CAPITAL RESOURCES

     Our primary cash requirements include working capital (primarily
inventory), debt service obligations and capital expenditures. We finance our
cash requirements with cash flow from operations, funds from our leasing
facility and borrowings under our revolving credit facility. At August 1, 1999,
we had net working capital of approximately $365.8 million and total liquidity
(cash plus availability under our revolving credit facility) of approximately
$63.0 million. We also have access to an off-balance sheet operating lease
facility that is used to finance new store construction. The facility provides
up to $112.2 million of funding for the acquisition and development of up to 94
new stores through December 31, 2000. As of August 1, 1999, none of this $112.2
million leasing facility had been utilized. Under a similar agreement that
expired on May 31, 1999 with respect to the addition of new properties, we had
approximately $94.6 million committed, with $34.7 million remaining to be funded
for stores that were previously identified for development but not completed by
May 31, 1999. Other than the borrowings associated with the acquisition
discussed below and the PACCAR and AIS acquisitions (see note 7 to the
Consolidated Financial Statements), we believe that cash flow from operations
combined with the availability of funds under the leasing facility and the
revolving credit facility will be sufficient to support our operations and
liquidity requirements for the foreseeable future.

     We paid approximately $62.1 million in cash for substantially all the
assets and assumed certain current liabilities and indebtedness of Big Wheel.
The acquisition was funded with proceeds from the Senior Credit Facility. In
connection with the acquisition, we amended and restated the Senior Credit
Facility to provide an additional $125.0 million of senior term loan borrowing
ability. We used $63.7 million, which included $1.6 million in debt issuance
costs, of this facility in conjunction with the Big Wheel acquisition and the
remaining $61.3 million was used to fund transition costs and to reduce the
balance of the revolving credit portion of the Senior Credit Facility.

     We are in the process of converting the Big Wheel stores that we acquired
in the second quarter of fiscal 1999 to the Checker name and store format and
integrating these stores into our operations. In connection with the integration
of the Big Wheel stores, we will incur one-time transition and integration
expenses estimated to be $7.0 million, consisting primarily of grand opening
advertising, training and re-merchandising costs. Approximately $0.6 million of
such expenses were incurred during the second quarter of fiscal 1999 with the
balance expected to be incurred during the third and fourth quarters of fiscal
1999. In addition, we will incur one-time capital expenditures of approximately
$6.0 million, consisting primarily of expenditures related to equipment, store
fixtures, signage and the installation of our store-level information systems in
the Big Wheel stores. All of such capital expenditures are expected to be
incurred during the third and fourth quarters of fiscal 1999.

     We acquired 88 stores and opened 53 new, relocated or expanded stores in
the first half of fiscal 1999 compared to 54 new, relocated or expanded stores
in the first half of fiscal 1998. In light of the recently announced
acquisitions of both the Big Wheel/Rossi stores and the Grand and Al's Auto
Supply stores, we have revised our new store development plan for the remainder
of fiscal 1999. During the second half of fiscal 1999, we now expect to open,
relocate or expand an additional 67 stores. We anticipate that the majority of
new, relocated or expanded stores will be financed by our lease facility under
arrangements structured as operating leases that require no net capital
expenditures by us except for fixtures and store equipment.

                                       10
<PAGE>   12

     For the first half of fiscal 1999, net cash used in operating activities
was $15.6 million compared to $16.7 million of cash provided by operating
activities during the comparable period of fiscal 1998. The largest component of
the change in cash flow from operating activities relates to our investment in
inventories, where $48.1 million of cash was used in operating activities during
fiscal 1999 compared to $1.2 million used for such purposes during fiscal 1998.
The increase in inventories reflects the increase in number of stores operated,
a seasonal build-up of certain products in anticipation of the higher volume
summer selling season and the acquisition of the Big Wheel/Rossi business.

     Net cash used in investing activities totaled $82.1 million for the first
half of fiscal 1999, compared to $17.0 million in the comparable period of
fiscal 1998. The increase in cash used in investing activities was primarily the
result of $62.1 million used in the Big Wheel acquisition.

     Net cash provided by financing activities totaled $96.8 million for the
first half of fiscal 1999 compared to $3.0 million in the comparable period of
fiscal 1998. In the 1999 period, we used $102.6 million of net borrowings under
the Senior Credit Facility primarily relating to the Big Wheel acquisition, made
payments of $4.8 million on capital lease obligations, incurred $1.6 million of
debt issuance costs, received $0.4 million of stockholder receivables, received
$0.7 million in proceeds from stock option exercises and paid $0.4 in connection
with other financing activities. In the 1998 period, we borrowed $65.0 million
under the Senior Credit Facility, made payments under the Senior Credit Facility
of $63.6 million, made payments of capital lease obligations of $4.5 million,
received $0.2 million of stockholder receivables and paid $0.2 million in
connection with other financing activities. In addition, during the 1998 period
we received gross proceeds of $172.5 million in connection with our IPO, which
were applied as follows: (1) $13.8 million to pay underwriters' discounts and
other transaction costs; (2) $50.0 million to retire all outstanding 12%
Subordinated Notes; (3) $43.8 million to retire certain of the 11% Senior
Subordinated Notes; (4) $53.8 million to pay certain outstanding balances under
the Senior Credit Facility; and (5) $4.9 million to pay premiums in connection
with the retirement of certain of the aforementioned debt instruments and the
balance to pay accrued interest and for general corporate purposes.

YEAR 2000 CONVERSION

     Historically, certain computerized systems have used two digits rather than
four to define the applicable year. Computer equipment and software and devices
with imbedded technology that are time-sensitive may recognize a date using "00"
as the year 1900 rather than the year 2000, resulting in system failures or
miscalculations. This problem is generally referred to as "the Year 2000 issue."

     During fiscal 1997, we began a comprehensive review of our systems and
applications for Year 2000 compliance. We also engaged an independent advisor to
evaluate and assist us with our Year 2000 program. To date, we have completed
the identification phase and we are 99% complete with the assessment phase of
our Year 2000 conversion. We have included both information technology, such as
purchased software and point-of-sale computer systems, and non-information
technology equipment, such as warehouse conveyor systems, in our evaluations. In
addition, we have identified our key third-party business partners and we are
coordinating with them to address potential Year 2000 issues. These issues
include data exchange with us as well as their shipping and warehousing
processes.

     Although we anticipate minimal business disruption will occur in our
systems as a result of the Year 2000 issue, possible consequences include a loss
of communications links with certain store locations, and the inability to
process transactions, send purchase orders, or engage in similar normal business
activities. We presently believe that with modifications to existing software
and conversions to new software, the risk of our Year 2000 conversion can be
mitigated. However, if we do not make the necessary modifications and
conversions, or do not complete them in a timely manner, it could have a
material adverse effect on our operations.

     We currently anticipate that our Year 2000 remediation and testing efforts
will be completed by November 15, 1999, although we will continue to run system
tests throughout the remainder of the year. As of August 1, 1999, we have
completed approximately 91% of our Year 2000 efforts. To date, we have incurred
and expensed approximately $0.9 million related to the assessment of and
preliminary efforts in connection with our Year 2000 conversion project. To
date, we have also capitalized approximately $5.8 million in connection with the
replacement of certain hardware and software applications.
                                       11
<PAGE>   13

     We estimate the total remaining cost of our Year 2000 conversion to be $1.4
million, which is being funded with lease financing and operating cash flows. Of
the total project cost, we attribute approximately $0.9 million to the purchase
of new hardware and software which will be capitalized. We will expense the
remaining $0.5 million as incurred during fiscal 1999.

     We have begun, but not yet completed, a comprehensive analysis of the
operational problems and costs (including loss of revenues) that would be
reasonably likely to result from our failure and the failure of certain third
parties to complete efforts necessary to achieve Year 2000 compliance on a
timely basis. We are also currently finalizing contingency plans which we expect
to be completed by the end of September 1999. Elements of our contingency plans
include: switching vendors, back-up systems or manual processes, and the
potential stockpiling of certain products prior to the Year 2000.

     The costs of our Year 2000 conversion and the date on which we plan to
complete the project are based upon our management's best estimates, which were
derived utilizing numerous assumptions of future events. We cannot guarantee
that we will achieve these estimates. Specific factors that could cause material
differences between our actual results and our estimates include: (1) the
availability and cost of personnel trained in this area; (2) the success of
third parties in their Year 2000 conversion plans; (3) the cost of implementing
contingency plans; and (4) the ability to locate and correct all relevant
computer codes and similar uncertainties.

FORWARD-LOOKING STATEMENTS

     The foregoing Management's Discussion and Analysis contains certain
forward-looking statements about the future performance of the Company that are
based on management's assumptions and beliefs in light of the information
currently available. These forward-looking statements are subject to
uncertainties and other factors that could cause actual results to differ
materially from those statements. Factors that may cause differences are
identified in our Annual Report on Form 10-K, and are incorporated herein by
reference.

                                       12
<PAGE>   14

                                    PART II

                               OTHER INFORMATION

ITEM 1.  LEGAL PROCEEDINGS

     We were served with a lawsuit that was filed in the Superior Court in San
Diego, California on May 4, 1998. The case is brought by two former store
managers and a former senior assistant manager. It purports to be a class action
for all present and former California store managers and senior assistant
managers and seeks overtime pay for a period beginning in May 1995 as well as
injunctive relief requiring overtime pay in the future. We were also served with
two other lawsuits purporting to be class actions filed in California state
courts in Orange and Fresno Counties by thirteen other former and current
employees. These lawsuits include similar claims to the San Diego lawsuit,
except that they also include claims for unfair business practices which seek
overtime from October 1994. The Orange County lawsuit initially included claims
for punitive damages and unlawful conversion, but the Court subsequently
dismissed both of these claims. The three cases have recently been "coordinated"
before one judge in San Diego County and discovery is being conducted by the
parties. If these cases are permitted by the courts to proceed as a class action
and are decided against us, our aggregate potential exposure could be material
to our results of operations or cash flows for the year in which the cases are
ultimately decided. We do not believe, however, that such an adverse outcome, if
it were to happen, would materially affect our financial position, operations or
cash flows in subsequent periods. Although at this stage in the litigation it is
difficult to predict their outcomes with any certainty, we believe that we have
meritorious defenses to all of these cases and intend to defend them vigorously.

     We currently and from time to time are involved in other litigation
incidental to the conduct of our business. The damages claimed against us in
some of these litigations are substantial. Although the amount of liability that
may result from these matters cannot be ascertained, we do not currently believe
that, in the aggregate, they will result in liabilities material to our
consolidated financial condition, results of operations or cash flow.

ITEM 2.  CHANGES IN SECURITIES AND USE OF PROCEEDS

     NONE

ITEM 3.  DEFAULTS UPON SENIOR SECURITIES

     NONE

                                       13
<PAGE>   15

ITEM 4.  SUBMISSION OF MATTERS TO A VOTE OF SECURITY HOLDERS

     We held our annual meeting of stockholders on June 8, 1999. The following
are the results of certain matters voted upon at the meeting:

I. Stockholders elected thirteen directors to serve until the 2000 Annual
   Meeting of Stockholders. The stockholders voted as follows:

<TABLE>
<CAPTION>
DIRECTORS                                                   VOTE FOR     WITHHELD
---------                                                  ----------    ---------
<S>                                                        <C>           <C>
Maynard Jenkins..........................................  25,419,426      231,610
James Bazlen.............................................  25,419,451      231,585
John F. Antioco..........................................  25,186,751      464,285
James O. Egan............................................  25,414,421      236,615
Morton Godlas............................................  25,439,136      211,900
Charles K. Marquis.......................................  25,418,451      232,585
Christopher J. O'Brien...................................  24,354,667    1,296,369
Charles J. Philippin.....................................  25,418,451      232,585
Robert Smith.............................................  25,418,481      232,555
Christopher J. Stadler...................................  25,418,406      232,630
Jules Trump..............................................  25,419,481      231,555
Eddie Trump..............................................  25,413,481      237,555
Savio W. Tung............................................  25,418,481      232,555
</TABLE>

II. Stockholders ratified the appointment of PricewaterhouseCoopers LLP as
    independent accountants for the 1999 fiscal year ending January 30, 2000.
    The stockholders voted as follows:

        For:  25,648,971  Against:  1,065  Abstain:  1,000

III. Stockholders approved the CSK Auto Corporation Directors Stock Plan, which
     allows us to make stock-based awards to our non-employee directors of up to
     an aggregate of 50,000 shares of common stock. The stockholders voted as
     follows:

        For:  23,094,405  Against:  2,554,906  Abstain:  1,725

IV. Stockholders approved the 1999 Amendment and Restatement to the 1996
    Executive Stock Option Plan, increasing the maximum number of shares for
    which we may grant options to a total of 744,200 shares of common stock. The
    stockholders voted as follows:

        For:  18,861,379  Against:  6,775,087  Abstain:  14,570

V. Stockholders approved an amendment to the Terms for Issuance of Bonus Options
   to certain of our executives under the Amended and Restated 1996 Employee
   Stock Option Plan. The stockholders voted as follows:

        For:  20,105,337  Against:  5,531,229  Abstain:  14,470

VI. Stockholders approved the adoption of the 1999 Employee Stock Option Plan,
    which allows us to grant options to our employees of up to a maximum of
    750,000 shares of common stock. The stockholders voted as follows:

        For:  18,142,165  Against:  7,507,701  Abstain:  1,170

VII. Stockholders approved the adoption of the 1999 Executive Incentive Program
     covering our two most senior executives. The stockholders voted as follows:

        For:  25,594,357  Against:  55,409  Abstain:  1,270

ITEM 5.  OTHER INFORMATION

     NONE

                                       14
<PAGE>   16

ITEM 6.  EXHIBITS AND REPORTS ON FORM 8-K

     (a)  Exhibits:

<TABLE>
<S>    <C>
3.01   Restated Certificate of Incorporation of the Company,
       incorporated herein by reference to Exhibit 3.01 of the
       Company's annual report on Form 10-K, filed on May 4, 1998
       (File No. 001-13927).
3.02   Certificate of Correction of the Company, incorporated
       herein by reference to Exhibit 3.02 of the Company's annual
       report on Form 10-K, filed on May 4, 1998 (File No.
       001-13927).
3.03   Amended and Restated By-Laws of the Company, incorporated
       herein by reference to Exhibit 3.03 of the Company's annual
       report on Form 10-K, filed on April 28, 1999 (File No.
       001-13927).
4.01   Second Amended and Restated Credit Agreement, dated as of
       June 30, 1999, among CSK Auto, Inc., The Chase Manhattan
       Bank, Lehman Commercial Paper Inc. and the lenders from time
       to time parties thereto.
27.01  Financial Data Schedule.
</TABLE>

     (b)  Reports on Form 8-K: None

                                       15
<PAGE>   17

                                   SIGNATURE

     Pursuant to the requirements of the Securities Exchange Act of 1934, the
Registrant has duly caused this report to be signed on its behalf by the
undersigned thereunto duly authorized.

                                       CSK Auto Corporation

                                       By: /s/ DON W. WATSON
                                         ---------------------------------------
                                         Don W. Watson
                                         Chief Financial Officer

DATED:  September 14, 1999

                                       16
<PAGE>   18

                                 EXHIBIT INDEX

<TABLE>
<CAPTION>
EXHIBIT NO.                           DESCRIPTION
-----------                           -----------
<S>           <C>
3.01          Restated Certificate of Incorporation of the Company,
              incorporated herein by reference to Exhibit 3.01 of the
              Company's annual report on Form 10-K, filed on May 4, 1998
              (File No. 001-13927).
3.02          Certificate of Correction of the Company, incorporated
              herein by reference to Exhibit 3.02 of the Company's annual
              report on Form 10-K, filed on May 4, 1998 (File No.
              001-13927).
3.03          Amended and Restated By-Laws of the Company, incorporated
              herein by reference to Exhibit 3.03 of the Company's annual
              report on Form 10-K, filed on April 28, 1999 (File No.
              001-13927).
4.01          Second Amended and Restated Credit Agreement, dated as of
              June 30, 1999, among CSK Auto, Inc., The Chase Manhattan
              Bank, Lehman Commercial Paper Inc. and the lenders from time
              to time parties thereto.
27.01         Financial Data Schedule.
</TABLE>