<PAGE>


                       SECURITIES AND EXCHANGE COMMISSION

                             WASHINGTON, D.C. 20549

                                 FORM 10-QSB/A

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

         For the quarterly period ended JUNE 30, 2000

                                       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 000-25979

                             WESTERN SIERRA BANCORP
              ----------------------------------------------------
             (Exact name of registrant as specified in its charter)


                CALIFORNIA                         680390121
      ------------------------------     ------------------------------
     (State or other jurisdiction of    (IRS Employer Identification No.)
      incorporation or organization)

      3350 COUNTRY CLUB DRIVE, SUITE 202, CAMERON PARK, CALIFORNIA 95682
      ------------------------------------------------------------------
             (Address of principal executive offices) (Zip Code)

        (Registrant's telephone number, including area code) 530-677-5600


 ------------------------------------------------------------------------------
              (Former name, former address and former fiscal year,
                         if changed since last report.)

         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  / /

                APPLICABLE ONLY TO ISSUERS INVOLVED IN BANKRUPTCY
                   PROCEEDINGS DURING THE PRECEDING FIVE YEARS

         Indicate by check mark whether the registrant has filed all documents
and reports required to be filed by Sections 12, 13 or 15(d) of the Securities
Exchange Act of 1934 subsequent to the distribution of securities under a plan
confirmed by a court. Yes  / /  No  /X/

                      APPLICABLE ONLY TO CORPORATE ISSUERS

         Indicate the number of shares outstanding of each of the issuer's
classes of common stock, as of the latest practicable date.

Common Stock - Issued and outstanding  3,242,317  shares at June 30, 2000.


<PAGE>


                            WESTERN SIERRA BANCORP

                                     INDEX

<TABLE>
<CAPTION>

                                                                                                         PAGE
                                                                                                         ----
<S>                                                                                                      <C>
PART I.       FINANCIAL INFORMATION

         Item 1.  Financial Statements

                  Consolidated Balance Sheets - June 30, 2000, December 31, 1999                            2

                  Consolidated Statements of Income - Three and Six Months
                      Ended June 30, 2000 and 1999                                                          3

                  Consolidated Statements of Cash Flows - Six Months Ended
                      June 30, 2000 and 1999                                                              4-5

                  Notes to Consolidated Financial Statements                                              6-9

         Item 2.  Management's Discussion and Analysis of Financial Condition                            9-17
                  and Results of Operations

         Item 3.  Quantitative and Qualitative Disclosures about Market Risks                              17

Part II.      OTHER INFORMATION

         Item 1.  Legal Proceedings                                                                        18

         Item 2.  Changes in Securities and Use of Proceeds                                                18

         Item 3.  Defaults Upon Senior Securities                                                          18

         Item 4.  Submission of Matters to a Vote of Security Holders                                      18

         Item 5.  Other Information                                                                        18

         Item 6.  Exhibits and Reports on Form 8-K                                                         18

</TABLE>

<PAGE>

PART 1 - FINANCIAL INFORMATION

ITEM 1.  CONSOLIDATED FINANCIAL STATEMENTS

WESTERN SIERRA BANCORP

CONSOLIDATED BALANCE SHEETS
      (IN THOUSANDS)

<TABLE>
<CAPTION>
                                                                        JUNE 30,              DECEMBER 31,
                                                                         2000                    1999
                                                                      (UNAUDITED)              (AUDITED)
                                                                       ---------              ---------
<S>                                                                    <C>                    <C>
                            ASSETS
Cash and due from banks                                                 $ 22,137               $ 20,400
Federal funds sold                                                        41,175                  6,675
Interest bearing deposits in banks                                           693                    891
Loans held for sale                                                        1,790                    964
Trading securities                                                             4                    175
Available-for-sale investment securities                                  57,739                 55,944
Held-to-maturity investment securities
    (market value of $12,510 in 2000 and
    $14,014 in 1999)                                                      12,865                 14,205
Loans and leases, less allowance for loan and
    lease losses of $4,002 in 2000 and $3,794
    in 1999 (Note C)                                                     297,872                270,562
Other real estate, net                                                       504                    715
Bank premises and equipment, net                                          10,261                  9,971
Accrued interest receivable and other assets                              12,548                 11,381
                                                                       ---------              ---------

                                                                        $457,588               $391,883
                                                                       =========              =========

                        LIABILITIES AND
                     SHAREHOLDERS' EQUITY

Deposits:

    Non-interest bearing                                                $ 88,005               $ 71,594
    Interest bearing                                                     325,489                271,590
                                                                       ---------              ---------
              Total deposits                                             413,494                343,184

    Short-term borrowings                                                  8,600                 15,300
    Accrued interest payable and other liabilities                         3,425                  2,484
                                                                       ---------              ---------
              Total liabilities                                          425,519                360,968
                                                                       ---------              ---------
Shareholders' equity:

    Preferred stock - no par value; 10,000,000
       shares authorized; none issued                                          -                      -
    Common stock - no par value; 10,000,000
       shares authorized; issued and outstanding -                        18,537                 18,812
       3,242,317 shares in 2000 and 3,236,134
       shares in 1999
    Retained earnings                                                     15,723                 14,341
    Unearned ESOP shares                                                    (500)                  (300)
    Accumulated other comprehensive loss                                  (1,691)                (1,938)
                                                                       ---------              ---------

              Total shareholders' equity                                  32,069                 30,915
                                                                       ---------              ---------

                                                                        $457,588               $391,883
                                                                       =========              =========
</TABLE>

The accompanying notes are an integral part of these financial statements.

                                       2
<PAGE>

PART 1 - FINANCIAL INFORMATION (Continued)

ITEM 1.  CONSOLIDATED FINANCIAL STATEMENTS (Continued)

WESTERN SIERRA BANCORP (Continued)

CONSOLIDATED STATEMENTS OF INCOME (UNAUDITED)

<TABLE>
<CAPTION>

(IN THOUSANDS)                                 THREE MONTHS ENDED                    SIX MONTHS ENDED
                                          ----------------------------         ----------------------------
                                            JUNE 30,          JUNE 30,          JUNE 30,          JUNE 30,
                                             2000              1999               2000             1999
                                          ----------        ----------         ----------       ----------
<S>                                       <C>               <C>                <C>              <C>
Interest income:
   Interest and fees on loans and
     leases                               $    7,159        $    5,509         $   13,480       $   10,708
   Interest on investment securities:
     Taxable                                     781             1,013              1,617            2,069
     Exempt from Federal income
       taxes                                     193               203                417              412
   Interest on Federal funds sold                359               233                589              501
                                          ----------        ----------         ----------       ----------
       Total interest income                   8,492             6,958             16,103           13,690

Interest expense on deposits                   3,537             2,538              6,458            5,123
Interest on short-term borrowings                111                94                294              175
                                          ----------        ----------         ----------       ----------
       Net interest income                     4,844             4,326              9,351            8,392
Provision for loan and lease losses
   (Note C)                                      180               185                340              440
       Net interest income after          ----------        ----------         ----------       ----------
         provision for loan and
         lease losses                          4,664             4,141              9,011            7,952
                                          ----------        ----------         ----------       ----------
Non-interest income:
   Service charges and fees                      615               461              1,211              930
   Other income                                  196               396                393              849
                                          ----------        ----------         ----------       ----------
       Total non-interest income                 811               857              1,604            1,779
                                          ----------        ----------         ----------       ----------
Other expenses:
   Salaries and employee benefits              2,082             1,724              3,992            3,579
   Occupancy and equipment                       593               489              1,192            1,178
   Merger and acquisition costs                  899               110                899              110
   Other                                       1,110             1,577              2,283            2,653
                                          ----------        ----------         ----------       ----------
       Total other expenses                    4,684             3,900              8,366            7,520
                                          ----------        ----------         ----------       ----------

       Income before income taxes                791             1,098              2,249            2,211
Income taxes                                     247               372                730              735
                                          ----------        ----------         ----------       ----------
       Net income                         $      544        $     726          $    1,519       $    1,476
                                          ==========        ==========         ==========       ==========

Basic earnings per share                  $    0.17              0.23               0.47             0.46
Weighted average shares of common stock    3,249,328         3,202,103          3,244,335        3,188,447

Diluted earnings per share                $    0.16              0.22               0.46             0.44
Weighted average shares of common stock
    and common stock equivalents           3,312,749         3,343,498          3,316,825        3,339,629
</TABLE>

The accompanying notes are an integral part of these financial statements.

                                       3
<PAGE>

PART 1 - FINANCIAL INFORMATION (Continued)

ITEM 1.  CONSOLIDATED FINANCIAL STATEMENTS (Continued)

WESTERN SIERRA BANCORP (Continued)

CONSOLIDATED STATEMENTS OF CASH FLOWS (UNAUDITED)

<TABLE>
<CAPTION>

                                                                                SIX MONTHS ENDED
                                                                        --------------------------------
(IN THOUSANDS)                                                           JUNE 30,               JUNE 30,
                                                                          2000                   1999
                                                                        ---------              ---------
<S>                                                                     <C>                    <C>
Cash flows from operating activities:
    Net income                                                          $  1,519               $  1,476
    Adjustments to reconcile net income to cash
       provided by operating activities:
          Provision for loan and lease losses                                340                    440
          Depreciation and amortization                                      705                    626
          Deferred loan origination costs and fees, net                       (2)                    83
          Proceeds from sale of trading securities                           171                     18
          Loss on sale of available for sale securities                                             (65)
          Gain on sale of other real estate                                   (8)
          Provision for losses on other real estate                           19                     14
          (Increase) decrease  in loans held for sale                       (826)                 2,726
          Increase in accrued interest receivable and other
              assets                                                        (860)                (2,438)
          Increase (decrease) in accrued interest payable and
              other liabilities                                              941                   (416)
                                                                        ---------              ---------
                 Net cash provided by operating
                    activities                                             1,999                  2,464
                                                                        ---------              ---------

Cash flows from investing activities:
    Net decrease in interest-bearing deposits
       in banks                                                              198                  2,966
    Proceeds from the sale and call of available-for-sale
       investment securities                                                 669                  6,751
    Proceeds from matured available-for-sale investment
       securities                                                                                 3,100
    Purchases of available-for-sale investment securities                 (5,864)                (5,892)
    Purchases of held-to-maturity investment securities                                          (1,499)
    Proceeds from matured held-to-maturity investment securities             150
    Principal repayments received from available-for-sale
       SBA pools and mortgage-backed securities                            3,281                  2,514
    Principal repayments received from held-to-maturity
       mortgage-backed securities                                          1,092                    713
    Net increase in loans and leases                                     (27,853)               (27,964)
    Proceeds from sale of other real estate                                  406
    Purchases of premises and equipment                                     (813)                  (179)
                                                                        ---------              ---------

                 Net cash used in investing
                    activities                                           (28,734)               (19,490)
                                                                        ---------              ---------

</TABLE>

                                   (Continued)

                                       4
<PAGE>

PART 1 - FINANCIAL INFORMATION (Continued)

ITEM 1.  CONSOLIDATED FINANCIAL STATEMENTS (Continued)

WESTERN SIERRA BANCORP (Continued)

CONSOLIDATED STATEMENTS OF CASH FLOWS (UNAUDITED) (Continued)

<TABLE>
<CAPTION>


                                                                                     SIX MONTHS ENDED
                                                                             ------------------------------
                                                                             JUNE 30,              JUNE 30,
(IN THOUSANDS)                                                                 2000                  1999
                                                                             --------              --------
<S>                                                                          <C>                   <C>
Cash flows from financing activities:
    Net increase in demand, interest-bearing and savings
       deposits                                                              $ 32,611              $  2,276
    Net increase (decrease) in time deposits                                   37,699                (8,382)
    Net (decrease) increase in short-term borrowings                           (6,700)                2,850
    Proceeds from ESOP loan                                                                             304
    Increase in unearned ESOP shares                                             (200)
    Proceeds from the exercise of stock options                                   142                   342
    Payment of cash dividends                                                    (164)                 (150)
    Payment for fractional shares                                                                       (26)
    Reacquisition of common stock                                                (416)
                                                                             --------              --------
                 Net cash provided by (used in) financing
                    activities                                                 62,972                (2,786)
                                                                             --------              --------
                 Increase (decrease) in cash and cash
                    equivalents                                                36,237               (19,812)

Cash and cash equivalents at beginning of period                               27,075                54,410
                                                                             --------              --------

Cash and cash equivalents at end of period                                  $  63,312              $ 34,598
                                                                            =========              ========

</TABLE>



The accompanying notes are an integral part of these financial statements.


                                      5


<PAGE>

PART 1 - FINANCIAL INFORMATION (Continued)

ITEM 1.  CONSOLIDATED FINANCIAL STATEMENTS (Continued)

WESTERN SIERRA BANCORP (Continued)

NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (UNAUDITED)

NOTE A - BASIS OF PRESENTATION

The financial information for Western Sierra Bancorp and Subsidiaries (the
"Company") included in this document is unaudited (although the December 31,
1999 information is derived from audited financial statements) but has been
prepared in accordance with generally accepted accounting principles for interim
financial statements and the rules and regulations of the Securities and
Exchange Commission (SEC) and, in the opinion of management, includes all
adjustments (normal recurring entries only) necessary for a fair presentation of
results for such interim periods. Certain information and note disclosures
normally included in financial statements prepared in accordance with generally
accepted accounting principles have been omitted in accordance with SEC rules
and regulations. These statements should therefore be read in conjunction with
the Company's Annual Report on Form 10-KSB for the year ended December 31, 1999.

In preparing such consolidated financial statements, management is required to
make estimates and assumptions that affect the reported amounts of assets and
liabilities as of the date of the balance sheet and revenues and expenses for
the period. Actual results could differ significantly from those estimates.
Material estimates that are particularly susceptible to significant change
include, but are not limited to, the determination of the allowance of loan
losses, valuation of collateral and assessment of problem loans.

NOTE B - MERGERS AND ACQUISITIONS

On May 31, 2000, the Company completed its acquisition of Sentinel Community
Bank (SCB) through the merger of SCB with and into the Company's wholly owned
subsidiary, Western Sierra National Bank.  The Company exchanged 719,814
shares of its common stock (after adjustment for fractional shares) for all
common stock of SCB.  Each share of SCB was exchanged for 1.491 shares of the
Company.

The merger has been accounted for as a pooling of interests and, accordingly,
all prior period financial statements have been restated to include the
combined results of operations, financial position and cash flows of the
Company and SCB.  Information concerning the common stock and per share data
has been restated on an equivalent share basis.

There were no material transactions between the Company or its bank
subsidiaries and SCB prior to the merger, and the effects of conforming the
accounting policies of SCB to those of the Company were not material.

Selected financial information for the combining entities included in the
consolidated statements of income for the five months ended May 31, 2000 and
the three and six month periods ended June 30, 1999 is as follows:

<TABLE>
<CAPTION>
                                 Five Months         Three Months         Six Months
                                 Ended May 31,       Ended June 30,      Ended June 30,
(In thousands)                       2000                1999                 1999
                               ----------------     ---------------     ----------------
<S>                            <C>                  <C>                 <C>
Net interest income:
 Western Sierra Bancorp and
   Subsidiaries                $          6,149     $         3,467      $         6,655
 Sentinel Community Bank                  1,544                 859                1,737
                               ----------------     ---------------     ----------------

     Combined                  $          7,693     $         4,326      $         8,392
                               ================     ===============     ================


Net income:
 Western Sierra Bancorp and
   Subsidiaries                $          1,368     $           641      $         1,233
 Sentinel Community Bank                     22                  85                  243
                               ----------------     ---------------     ----------------

     Combined                  $          1,390     $           726      $         1,476
                               ================     ===============     ================
</TABLE>


Effective April 30, 1999, Lake Community Bank and Roseville 1st Community
Bancorp were merged into the Company in stock-for-stock transactions which were
accounted for under the pooling-of-interests method of accounting. Accordingly,
the Company's consolidated financial statements have been restated for all
periods prior to the business combinations.

On May 5, 2000 Roseville 1st National Bank (R1NB) merged into Western Sierra
National Bank (WSNB).  All assets and liabilities of R1NB were transferred to
WSNB and R1NB ceased to exist as a separate entity.

In August 2000 the Company entered into an agreement to purchase the Columbia
branch of Pacific State Bank.  In this transaction, the Company will acquire
approximately $4 million in deposits, to include paying a premium of 1% of
the average balance of the branch's deposits 30 days prior to the
consummation date and approximately $17,000 in fixed assets.  This
transaction has been approved by the Company's Board of Directors and is
subject to regulatory approval.

NOTE C - LOANS AND LEASES

Outstanding loans and leases are summarized below:

<TABLE>
<CAPTION>

                                                                              June 30,          December 31,
(In thousands)                                                                  2000                1999
                                                                              --------         -------------
<S>                                                                           <C>                <C>
Commercial                                                                    $ 39,909           $ 51,206
Real estate - mortgage                                                         203,396            157,368
Real estate - construction                                                      43,610             41,758
Lease financing                                                                  1,548              1,763
Installment                                                                      6,761              7,679
Agricultural                                                                     7,436             15,370

                                                                              --------           --------
                                                                               302,660            275,144

Deferred loan and lease origination fees and costs, net                           (786)              (788)
Allowance for loan and lease losses                                             (4,002)            (3,794)
                                                                              --------           --------

                                                                              $297,872          $ 270,562
                                                                              ========          =========
</TABLE>

                                      6


<PAGE>

PART 1 - FINANCIAL INFORMATION (Continued)

ITEM 1.  CONSOLIDATED FINANCIAL STATEMENTS (Continued)

WESTERN SIERRA BANCORP (Continued)

NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (UNAUDITED) (Continued)

NOTE C - LOANS AND LEASES (Continued)

Changes in the allowance for loan and lease losses were as follows:

<TABLE>
<CAPTION>
                                         Three Months Ended                      Six Months Ended
                                              June 30,                                June 30,
(In thousands)                        2000                1999                2000                1999
                                    ---------          ---------           ---------           ---------
<S>                                 <C>                <C>                 <C>                 <C>
Balance, beginning of year          $   3,927          $   3,265           $   3,793           $   2,987
Provision charged to                      180                185                 340                 440
    operations
Losses charged to allowance              (129)              (163)               (189)               (206)
Recoveries                                 24                  0                  58                  66
                                    ---------          ---------           ---------           ---------
                                    $   4,002          $   3,287           $   4,002           $   3,287
                                    =========          =========           =========           =========
</TABLE>

NOTE D - EARNINGS PER SHARE

A reconciliation of the numerators and denominators of the basic and diluted
earnings per share computations is as follows:

<TABLE>
<CAPTION>

(In thousands except for per
share information)
                                                                                 Weighted
                                                                                  Average
                                                                                 Number of
            For the Three Months                               Net                Shares             Per Share
                  Ended                                       Income            Outstanding           Amount
            --------------------                           -----------         ------------         ----------
<S>                                                        <C>                  <C>                <C>
JUNE 30, 2000

Basic earnings per share                                     $   544              3,249,328         $    0.17
                                                                                                    =========
Effect of dilutive stock options                                                     63,421
                                                             -------            -----------

Diluted earnings per share                                   $   544               3,312,749        $    0.16
                                                             =======            ============        =========
JUNE 30, 1999

Basic earnings per share                                     $   726               3,202,103        $    0.23
                                                                                                    ==========
Effect of dilutive stock options                                                     141,395
                                                             -------            ------------

Diluted earnings per share                                   $   726               3,343,498        $    0.22
                                                             =======            ============        ==========
</TABLE>
                                      7

<PAGE>


PART 1 - FINANCIAL INFORMATION (Continued)

ITEM 1.  CONSOLIDATED FINANCIAL STATEMENTS (Continued)

WESTERN SIERRA BANCORP (Continued)

NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (UNAUDITED) (Continued)

NOTE D - EARNINGS PER SHARE (Continued)

<TABLE>
<CAPTION>
(In thousands, except for
per share information)
                                                                               Weighted
                                                                                Average
                                                                               Number of
       For the Six Months                                    Net                Shares             Per Share
            Ended                                           Income            Outstanding           Amount
--------------------------------                          -----------         -----------         -----------
<S>                                                       <C>                 <C>                 <C>
JUNE 30, 2000

Basic earnings per share                                    $1,519              3,244,335            $0.47
                                                                                                    ======
Effect of dilutive stock options                                                   72,490
                                                          -----------         -----------           ------
Diluted earnings per share                                  $1,519              3,316,825            $0.46
                                                          ===========         ===========           ======
JUNE 30, 1999

Basic earnings per share                                    $1,476              3,188,447            $0.46
                                                                                                    ======
Effect of dilutive stock options                                                  151,182
                                                          -----------         -----------
Diluted earnings per share                                  $1,476              3,339,629            $0.44
                                                          ===========         ===========           ======
</TABLE>

NOTE E - COMPREHENSIVE INCOME

Comprehensive income is reported in addition to net income for all periods
presented.  Comprehensive income is a more inclusive financial reporting
methodology that includes disclosure of other comprehensive income (loss)
that historically has not been recognized in the calculation of net income.
Unrealized gains and losses on the Company's available-for-sale investment
securities are included in other comprehensive income (loss).  An analysis of
comprehensive income (loss) follows:

<TABLE>
<CAPTION>

                                                                                 For the Six Months Ended
                                                                              -----------------------------
                                                                              June 30,              June 30,
(In thousands)                                                                 2000                  1999
                                                                              -------               -------
<S>                                                                           <C>                   <C>
Net income                                                                    $   544               $   726
Other comprehensive income (loss) net of tax:
    Unrealized gains (losses) on available-for-sale
       investment securities                                                      247                (1,140)
                                                                              -------               -------
          Total comprehensive income (loss)                                   $   791               $  (414)
                                                                              =======               =======

</TABLE>

<TABLE>
<CAPTION>

                                                                              For the Three Months Ended
                                                                              --------------------------
                                                                              June 30,           June 30,
                                                                               2000               1999
                                                                              -------            -------
<S>                                                                           <C>                <C>
Net income                                                                    $ 1,519            $ 1,476
Other comprehensive income (loss), net of tax:
    Unrealized gains (losses) on available-for-sale
       investment securities                                                      111               (893)
                                                                              -------            -------
          Total comprehensive income                                          $ 1,630            $   583
                                                                              =======            =======
</TABLE>

                                      8
<PAGE>


PART 1 - FINANCIAL INFORMATION (Continued)

ITEM 1.  CONSOLIDATED FINANCIAL STATEMENTS (Continued)

WESTERN SIERRA BANCORP (Continued)

NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (UNAUDITED) (Continued)

NOTE F - NEW ACCOUNTING PRONOUNCEMENTS

In June 1998, the Financial Accounting Standards Board issued SFAS 133,
ACCOUNTING FOR DERIVATIVE INSTRUMENTS AND HEDGING ACTIVITIES, which was
subsequently amended by SFAS 137 to delay the effective date of SFAS 133 to
fiscal quarters of fiscal years beginning after June 15, 2000. This Statement
establishes accounting and reporting standards for derivative instruments,
including certain derivative instruments embedded in other contracts, and for
hedging activities. It requires that entities recognized all derivatives as
either assets or liabilities on the balance sheet and measure those
instruments at fair value. Management does not believe that the adoption of
SFAS 133 will have a significant impact on its financial position and results
of operations when implemented.

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

Certain matters discussed or incorporated by reference in the Quarterly
Report on form 10-QSB are forward-looking statements that are subject to
risks and uncertainties that could cause actual results to differ materially
from those projected. Such risks and uncertainties include, but are not
limited to, variances in actual versus projected growth, changes in rates
charged on interest-earning assets and interest-paying liabilities, credit
quality and effects of competition. Therefore, the information set forth
therein should be carefully considered when evaluating the business prospects
of the Company.

FINANCIAL CONDITION

Total assets increased by 16.76% to $457.6 million at June 30, 2000, from
$391.9 million at December 31, 1999. Total deposits increased by 20.48% to
$413.5 million at June 30, 2000 from $343.2 million at December 31, 1999.
This increase in deposits resulted in the corresponding increase in total
assets. The Company's total assets increased $65.7 million or 16.76% from
$391.9 million at December 31, 1999 to $457.6 at June 30, 2000. This increase
is primarily invested in a $34.5 million increase in Federal Funds sold and a
$27.3 million increase in the net loan portfolio. The majority of the
increases are directly attributable to efforts of Management to increase
investment and lending activity. During the same period, deposits increased
$70.3 million or 20.48% from $343.2 million at December 31, 1999 to $413.4
million at June 30, 2000. This increase is primarily due to an increase in
the Company's volume of time deposits which totaled $201 million at June 30,
2000 compared to $163 million at December 31, 1999, a $38 million increase.
Advances from the FHLB decreased $1.3 million from $9 million at December 31,
1999 to $7.7 million at June 30, 2000. During the same period Federal funds
purchased decreased from $6 million to zero. The Company had $1.691 million
and $1.938 million in unrealized losses (net of deferred tax benefits) at
June 30, 2000 and December 31, 1999, respectively, from market gains on the
Company's equity securities offset by market losses on the Company's
available-for-sale investment and mortgage-backed portfolios.

Net loans totaled $297.9 million at June 30, 2000, representing a 73.20% loan
to deposit ratio, compared to net loans of $270.6 million at December 31,
1999, representing a 80.17% loan to deposit ratio. The decrease in loan to
deposit ratio is due primarily to the rapid increase in deposits. This
deposit growth is temporarily invested in Federal Funds sold. Management
expects loans to grow during the remainder of 2000. In management's opinion,
the allowance for loan losses, totaling $4.0 million at June 30, 2000,
adequately provides for possible loan losses. This allowance represents 1.32%
of gross loans outstanding at the end of the second quarter.

RESULTS OF OPERATIONS FOR THE THREE MONTHS ENDED JUNE 30, 2000

NET INTEREST INCOME

                                      9
<PAGE>


Interest income increased 22.05% to $8,492 thousand for the quarter ended
June 30, 2000 from $6,958 thousand for the quarter ended June 30, 1999. The
increased interest income on loans and investments was primarily due to a 57
basis point increase in the yields realized on loans as a result of changes
in market conditions during the quarter ending June 30, 2000 as compared to
the quarter ended June 30, 1999.  In addition, total average earning assets
increased by $34,735 thousand at June 30, 2000 as compared to June 30, 1999.

Interest expense increased 38.60% to $3,648 thousand for the quarter ended
June 30, 2000 from $2,632 thousand for the quarter ended June 30, 1999. The
increase in interest expense during the three months ended June 30, 2000 was the
result of an overall increase in interest rates of approximately 98 basis
points over the three months ended June 30, 1999 on these deposits.

                                      10
<PAGE>


PART 1 - FINANCIAL INFORMATION (Continued)

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

WESTERN SIERRA BANCORP (Continued)

RESULTS OF OPERATIONS FOR THE THREE MONTHS ENDED JUNE 30, 2000 (Continued)

NET INTEREST INCOME (Continued)

The following table sets forth, on a tax-equivalent basis, certain
information relating to the Company's average balance sheet and reflects the
average yield earned on interest-earning assets, the average cost of
interest-bearing liabilities and the resulting net interest income for the
three month periods ended June 30, 2000 and 1999:


<TABLE>
<CAPTION>

                                                           Three Months Ended June 30,
                                                 2000                                      1999
                               -------------------------------------      -------------------------------------
                                Average        Income/        Yield/       Average        Income/        Yield/
(In thousands)                  Balance        Expense        Rate         Balance        Expense        Rate
                               --------        --------     --------      --------        --------     --------
<S>                            <C>             <C>          <C>           <C>             <C>          <C>
ASSETS
Earning assets:
   Commercial loans (1)        $ 43,031        $  1,086        10.10%     $ 44,807        $  1,336        11.93%
   Real estate loans (1)        242,952           5,931         9.76       181,851           4,030         8.86
   Installment loans (1)          7,304             142         7.76         5,671             143        10.09
                               --------        --------     --------      --------        --------     --------

       Sub-total loans          293,287           7,159        10.05       232,329           5,509         9.48

   Federal funds sold            36,497             359         3.93        23,358             233         3.99
   Investments (2)               70,091           1,051         6.00       109,453           1,297         4.74
                               --------        --------     --------      --------        --------     --------

       Total earning assets     399,875           8,569         8.57       365,140           7,039         7.73
                                               --------                                   --------
Less:  Allowance for loan        (3,887)                                    (2,622)
       losses

Cash and due from banks          19,091                                     17,367

Premises and equipment,
   net                            9,179                                      9,075

Accrued interest receivable
   and other assets              10,926                                     32,921
                               --------                                   --------

       Total assets            $435,184                                   $421,881
                               ========                                   ========
</TABLE>


                                      11
<PAGE>

PART 1 - FINANCIAL INFORMATION (Continued)

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

WESTERN SIERRA BANCORP (Continued)

RESULTS OF OPERATIONS FOR THE THREE MONTHS ENDED JUNE 30, 2000 (Continued)

NET INTEREST INCOME (Continued)

<TABLE>
<CAPTION>
                                                                   Three Months Ended June 30,
                                                         2000                                      1999
                                       ----------------------------------------  ---------------------------------------

                                           AVERAGE        INCOME/       YIELD/       AVERAGE        INCOME/       YIELD/
(In thousands)                             BALANCE        EXPENSE       RATE         BALANCE        EXPENSE       RATE
                                       -------------   -------------  ---------  -------------  -----------     --------
<S>                                    <C>            <C>            <C>         <C>            <C>            <C>
LIABILITIES AND SHAREHOLDERS' EQUITY
Interest-bearing demand,
   savings and time deposits              $318,339       $   3,537        4.44      $292,509       $   2,538       3.47
Short-term borrowings                        7,448             111        5.96         7,875              94       4.77
                                          --------       ---------     -------     ---------       ---------

       Total interest-
         bearing
         liabilities                       325,787           3,648        4.48       300,384           2,632       3.50
                                          --------                                ----------

Non-interest bearing
   deposits and other liabilities           79,382                                    92,385
                                          --------                                ----------

       Total liabilities                   405,169                                   392,769
                                          --------                                ----------

Common stock                                13,400                                    14,171
Retained earnings                           18,488                                    15,163
Accumulated other
   comprehensive loss                       (1,873)                                     (222)
                                          --------                                ----------

       Total shareholders'
         equity                             30,015                                    29,112
                                          --------                                ----------

       Total liabilities and
         shareholders'
         equity                           $435,184                                 $ 421,881
                                          ========                                 =========

Net interest income                                      $   4,921                                 $  4,064
                                                         =========                                 ========

Interest income as a per-
   centage of average
   earning assets                                           8.57                                       7.73

Interest expense as a
   percentage of average
   earning assets                                           3.65                                       2.89

Net yield on average
   earning assets (net
   interest margin)                                         4.92                                       4.84
</TABLE>

                                      12

<PAGE>

PART 1 - FINANCIAL INFORMATION (Continued)

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

WESTERN SIERRA BANCORP (Continued)

RESULTS OF OPERATIONS FOR THE THREE MONTHS ENDED JUNE 30, 2000 (Continued)

NET INTEREST INCOME (Continued)

(1) Loan amounts include nonaccrual loans, but the related interest income has
been included only for the period prior to the loan being placed on a nonaccrual
basis and interest actually received subsequent to that date.

(2) Applicable nontaxable yields have been calculated on a tax-equivalent
basis, based on a 40% average tax rate.

NON-INTEREST INCOME AND EXPENSES

Non-interest income decreased 5.37% to $811 thousand for the quarter ended
June 30, 2000 from $857 thousand for the quarter ended June 30, 1999. This
decrease was comprised of a $154 thousand or 33.4% increase in service
charges and fees which was offset by a $200 thousand or 50.5% decrease in
other non-interest income. The decrease in other non-interest income was due to
a decrease in the gains on the sale of loans and fees on the packaging of loans
by the mortgage department.

The allocation to the Provision for Loan Losses for the second quarter of 2000
was $180 thousand as compared to an allocation of $185 thousand for the second
quarter of 1999.

Other expenses increased 20.10% to $4,684 thousand for the quarter ended June
30, 2000 from $3,900 thousand for the quarter ended June 30, 1999. These
expenses represent the operational and administrative expenses of the
Company. In addition to normal recurring expenses, the second quarter of 2000
included $899 thousand in non-recurring merger related costs. Significant
expenses included in these merger costs included $380 thousand to buy out a
contract with Fiserve for data processing, $232 thousand in professional fees
and $41 thousand in printing costs. The prior year quarter ended June 30,
1999 included $110 thousand in these types of costs.

RESULTS OF OPERATIONS FOR THE SIX MONTHS ENDED JUNE 30, 2000

NET INTEREST INCOME

Interest income increased 17.63% to $16,103 thousand for the six months ended
June 30, 2000 from $13,690 thousand for the six months ended June 30, 1999.
The increased interest income on loans and investments was primarily due to a
change in the mix of the investment securities to loans, an increase in
average earning assets of $15,201 thousand and a 96 basis point increase in
total yield on earnings assets. (see the following schedule).

Interest expense increased 27.44% to $6,752 thousand for the six months ended
June 30, 2000 from $5,298 thousand for the six months ended June 30, 1999.
The increase in interest expense was the result of the increase in average
interest bearing accounts and certificates of deposits in 2000 over the same
period in 1999. In addition, the increase in interest expense can be
attributed to an 80 basis point increase in rates.

                                      13

<PAGE>

PART 1 - FINANCIAL INFORMATION (Continued)

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

WESTERN SIERRA BANCORP (Continued)

RESULTS OF OPERATIONS FOR THE SIX MONTHS ENDED JUNE 30, 2000 (Continued)

NET INTEREST INCOME (Continued)

The following table sets forth, on a tax-equivalent basis, certain information
relating to the Company's average balance sheet and reflects the average yield
earned on interest-earning assets, the average cost of interest-bearing
liabilities and the resulting net interest income for the six month periods
ended June 30, 2000 and 1999:

<TABLE>
<CAPTION>
                                                            Six Months Ended June 30,
                                                 2000                                      1999
                               ----------------------------------------  ---------------------------------------
                                   AVERAGE        INCOME/      YIELD/       AVERAGE        INCOME/       YIELD/
(In thousands)                     BALANCE        EXPENSE       RATE        BALANCE        EXPENSE       RATE
                               -------------   -------------  ---------  -------------  -----------     --------
<S>                              <C>             <C>            <C>         <C>            <C>           <C>
ASSETS
Earning assets:
   Commercial loans (1)          $ 46,405        $ 2,276        9.81%       $ 44,494       $  2,673       12.02%
   Real estate loans (1)          231,817         10,919        9.42         183,402          7,746        8.12
   Installment loans (1)            7,434            285        7.67           5,563            289       10.39
                                ---------        -------       -----        --------       --------       -----

       Sub-total loans            285,656         13,480        9.44         233,459         10,708        9.17

   Federal funds sold              26,423            589        4.46          23,941            501        4.19
   Investments (2)                 69,783          2,201        6.31         109,261          2,646        4.84
                                ---------        -------       -----        --------       --------       -----

       Total earning assets       381,862         16,270        8.52         366,661         13,855        7.56
                                                --------                                   --------

Less:  Allowance for loan
       losses                      (3,877)                                    (3,131)

Cash and due from banks            15,927                                     17,467

Premises and equipment,
   net                              9,611                                      8,614

Accrued interest receivable
   and other assets                14,888                                     31,795
                                ---------                                   --------

       Total assets              $418,411                                   $421,406
                                =========                                   ========
</TABLE>


                                      14
<PAGE>

PART 1 - FINANCIAL INFORMATION (Continued)

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

WESTERN SIERRA BANCORP (Continued)

RESULTS OF OPERATIONS FOR THE SIX MONTHS ENDED JUNE 30, 2000 (Continued)

NET INTEREST INCOME (Continued)

<TABLE>
<CAPTION>
                                                            Six Months Ended June 30,
                                                 2000                                      1999
                               ----------------------------------------  ---------------------------------------
                                   Average        Income/       Yield/       Average        Income/       Yield/
(In thousands)                     Balance        Expense       Rate         Balance        Expense       Rate
                               -------------   -------------  ---------  -------------  -----------     --------
<S>                              <C>             <C>           <C>           <C>           <C>            <C>
LIABILITIES AND SHAREHOLDERS'
   EQUITY
Interest-bearing demand,
   savings and time deposits     $301,369        $  6,458         4.29      $291,995      $  5,123        3.51
Short-term borrowings              10,071             294         5.84         6,937           175        5.05
                                 --------        --------      -------      --------      --------     --------


       Total interest-
         bearing
         liabilities              311,440           6,752         4.34       298,932         5,298        3.54
                                 --------        --------      -------      --------      --------     --------

Non-interest bearing deposits
   and other liabilities           76,354                                     93,309
                                 --------                                   --------

       Total liabilities          387,794                                    392,241
                                 --------                                   --------

Common stock                       13,503                                     14,172
Retained earnings                  18,986                                     15,220
Accumulated other com-
   prehensive loss                 (1,872)                                      (227)
                                 --------                                   --------

       Total shareholders'
         equity                    30,617                                     29,165
                                 --------                                   --------

       Total liabilities and
         shareholders'
         equity                  $418,411                                   $421,406
                                 ========                                   ========

Net interest income                              $  9,518                                  $ 8,557
                                                 ========                                  =======

Interest income as a per-
   centage of average
   earning assets                                    8.52                                     7.56

Interest expense as a
   percentage of average
   earning assets                                    3.54                                     2.56

Net yield on average
   earning assets (net
   interest margin)                                  4.98                                     4.67
</TABLE>

                                      15

<PAGE>

PART 1 - FINANCIAL INFORMATION (Continued)

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

WESTERN SIERRA BANCORP (Continued)

RESULTS OF OPERATIONS FOR THE SIX MONTHS ENDED JUNE 30, 2000 (Continued)

NET INTEREST INCOME (Continued)

(1) Loan amounts include nonaccrual loans, but the related interest income has
been included only for the period prior to the loan being placed on a nonaccrual
basis and interest actually received subsequent to that date.

(2) Applicable nontaxable yields have been calculated on a taxable-equivalent
basis, based on a 40% average tax rate.

NON-INTEREST INCOME AND EXPENSES

Non-interest income decreased 10% to $1,604 thousand for the six months ended
June 30, 2000 from $1,779 thousand for the six months ended June 30, 1999.
This decrease was due to a decrease in the gains on the sale of loans and
fees on the packaging of loans by the mortgage department.

In determining the appropriate level of the allowance for loan losses,
management considers various factors affecting the collectibility of loans,
to include economic conditions, past credit experience and the periodic
review of the Company's loan portfolio. The allocation to the Provision for
Loan Losses for the first six months of 2000 was $340 thousand as compared to
an allocation of $440 thousand for the first six months of 1999. Net losses
for the six months ended June 30, 2000 totaled $131 thousand as compared to
net losses which totaled $140 thousand for the same period in 1999.  The
decrease in the provision for loan losses is attributable to the overall
improvement in the credit quality of the Company's loans.

Other expenses increased 11.25% to $8,366 thousand for the six months ended
June 30, 2000 from $7,520 thousand for the six months ended June 30, 1999.
These expenses represent the operational and administrative expenses of the
Company and include the aforementioned non-recurring merger related expenses
of $899 thousand for the six months ended June 30, 2000 as compared to $110
thousand for the same period in 1999.

Net income for the six months ended June 30, 2000 totaled $1,519 thousand as
compared to net income of $1,476 thousand for the six months ended June 30,
1999.

LIQUIDITY

The Company's bank subsidiaries have a combined asset and liability
management program allowing them to monitor and maintain interest margins
during times of both rising and falling interest rates and to maintain
sufficient liquidity. Liquidity at each Bank subsidiary consists of cash and
due from banks, investments not pledged, federal funds sold and loans
available-for-sale. In addition, the Bank subsidiaries maintain lines of
credit with several correspondent banks and lines of credit with the Federal
Reserve Bank and the Federal Home Loan Bank. At June 30, 2000 the bank
subsidiaries had $8.6 million in short-term borrowings compared to a $15.3
million balance at December 31, 1999. It is the Company's intention to use
some of its deposit growth to retire this debt.

CAPITAL RESOURCES

Total shareholders' equity increased to $32.1 million at June 30, 2000 from
$30.9 million at December 31, 1999. The change was primarily due to net
income of $1,519 thousand during the six month period and a change in the
unrealized loss on available-for-sale securities of $247 thousand.

The Company and its bank subsidiaries are subject to various regulatory capital
requirements administered by the federal banking agencies. Under capital
adequacy guidelines and the regulatory framework for prompt corrective action,
the Company and each bank subsidiary must meet specific capital guidelines that
involve quantitative measures of assets, liabilities and certain off-balance
sheet items as calculated under regulatory accounting practices. The capital
amounts and classifications are also subject to qualitative judgements by the
regulators about components, risk weighting and other factors.


                                         16
<PAGE>

PART 1 - FINANCIAL INFORMATION (Continued)

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

WESTERN SIERRA BANCORP (Continued)

CAPITAL RESOURCES (Continued)

The following table outlines the Company's consolidated capital ratios at
June 30, 2000.

<TABLE>
<CAPTION>
                                                         June 30,             June 30,            December 31,
                                                          2000                  1999                  1999
                                                        ---------            ---------            -----------
<S>                                                      <C>                  <C>                  <C>
Total Risk-Based Capital Ratio
     Regulatory Requirement                              10.00%               10.00%                10.00%
     Western Sierra Bancorp                              11.65%               11.09%                12.20%
Tier 1 Risk-Based Capital Ratio
     Regulatory Requirement                               6.00%                6.00%                 6.00%
     Western Sierra Bancorp                              10.42%               10.03%                11.00%
Leverage Ratio
     Regulatory Requirement                               5.00%                5.00%                 5.00%
     Western Sierra Bancorp                               8.33%                7.62%                 8.50%
</TABLE>

The Company and each of its bank subsidiaries meet all the regulatory capital
requirements of a "well capitalized" institution.

ITEM 3.  QUANTITATIVE AND QUALITATIVE DISCLOSURE REGARDING MARKET RISK

The Company's bank subsidiaries periodically perform asset/liability analysis to
assess the sensitivity to changing market conditions. The following information
is extracted from the Form 10-KSB filed with the Securities and Exchange
Commission effective December 31, 1999.

Market risk is the risk of loss from adverse changes in market price and rates.
The Company's market risk arises primarily from interest rate risk inherent in
its loan and deposit functions and management activity monitors and manages this
inherent risk exposure. The Company does not have any market risk sensitive
instruments entered into for trading purposes. Management uses several different
tools to monitor its interest rate risk. One measure of exposure to interest
rate risk is gap analysis. A positive gap for a given period means that the
amount of interest-bearing assets maturing or otherwise repricing within such
period is greater than the amount of interest-bearing liabilities maturing or
otherwise repricing within the same period. The Company has a positive gap. In
addition, interest shock simulations are used to estimate the effect of certain
hypothetical rate changes. Based on these shock simulations, net interest income
is expected to rise with increasing rates and fall with declining rates.

The Company's positive gap is the result of the fact that the majority of its
investments have terms greater than five years on the asset side. On the
liability side, the majority of time deposits have average terms of
approximately six months, while savings accounts and other interest-bearing
transaction accounts have no contractual maturity date.

Taking into consideration that savings accounts and other interest-bearing
transaction accounts typically do not react immediately to changes in interest
rates, management has added loans tied to indices which change at a slower rate
than prime and more closely match liabilities. In addition, most of the
investments are held in the available-for-sale category in order to be able to
react to changes in interest rates.

There have not been any significant changes in the risk management profile since
December 31, 1999. See the Form 10-KSB filed effective that date for more
specific information.


                                      17

<PAGE>

PART II - OTHER INFORMATION

WESTERN SIERRA BANCORP (Continued)

ITEM 1.  LEGAL PROCEEDINGS

The Company is subject to legal proceedings and claims which arise in the
ordinary course of business. In the opinion of management, the amount of
ultimate liability with respect to these actions will not materially affect the
financial position or results of operations of the Company.

ITEM 2.  CHANGES IN SECURITIES AND USE OF PROCEEDS

Not applicable.

ITEM 3.  DEFAULTS UPON SENIOR SECURITIES

Not applicable.

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

On May 23, 2000, the annual meeting of the shareholders of Western Sierra
Bancorp was held for the purpose of voting on the following matters:

Proposal 1.     Approval of the merger agreement with Sentinel Community Bank
                (See Part 1, Item 1, Note B included herein for further details
                on this transaction).

                Voted For:        1,634,778
                Abstained:            8,033
                Against:              7,237
                Not Voted:          271,175

Proposal 2.     Amendment of Bylaws to eliminate cumulative voting in the
                election of directors.

                Voted For:        1,507,637
                Abstained:           16,421
                Against:            125,990
                Not Voted:          271,175

Proposal 3:     Election of directors:

<TABLE>
<CAPTION>
                              Voted For             Withheld
                              ---------             --------
<S>                           <C>                    <C>
Charles W. Bacchi             1,901,295              19,928
Barbara L. Cook               1,900,825              20,398
Kirk Doyle                    1,901,025              20,198
William J. Fisher             1,900,689              20,534
Gary D. Gall                  1,900,421              20,802
Richard L. Golemon            1,901,295              19,928
John Helms                    1,898,172              23,051
Howard Jahn                   1,901,025              20,198
Thomas Manz                   1,901,025              20,198
Harold S. Prescott, Jr.       1,901,295              19,928
Darol B. Rasmussen            1,901,295              19,928
Osvaldo I. Scariot            1,901,295              19,928
Richard C. Seeba              1,901,321              19,902
Joseph A. Surra               1,900,933              20,290
Howard "Bud" Van Lente        1,898,080              23,143
</TABLE>

ITEM 5.  OTHER INFORMATION

Not applicable.

ITEM 6.  EXHIBITS AND REPORTS ON FORM 8-K

A.       EXHIBITS

         Exhibit 27.  Financial Data Schedule

B.       REPORTS ON FORM 8-K

         During the six months ended June 30, 2000 the Company filed a Current
Report on Form 8-K, dated June 1, 2000, to report the merger with Sentinel
Community Bank. In addition the Company filed a Current Report on Form 8-K/A
that included Sentinel Community Bank financial statements for December 31,
1999 and 1998 and for the years ended December 31, 1999, 1998 and 1997, and
Independent Auditors Report.


                                      18

<PAGE>

SIGNATURES

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.

Date: August   , 2000.

                                                WESTERN SIERRA BANCORP



                                                /s/ GARY GALL
                                                -----------------------------
                                                Gary Gall
                                                President and
                                                Chief Executive Officer

                                                /s/ LESA FYNES
                                                -----------------------------
                                                Lesa Fynes
                                                Chief Financial Officer

                                      19