<PAGE>
 
                                 UNITED STATES
                       SECURITIES AND EXCHANGE COMMISSION
                              WASHINGTON, DC 20549
                                  FORM 10-QSB



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


    For the QUARTER ENDED SEPTEMBER 30, 1997 Commission file number: 0-11090


                             NAPA NATIONAL BANCORP
       (Exact name of Small Business Issuer as specified in its charter)


            CALIFORNIA                                  94-2780134
  (State or other jurisdiction of                     (IRS Employer
   incorporation or organization)                 Identification Number)


    901 MAIN STREET, NAPA, CALIFORNIA                     94559
(Address of principal executive offices)                (Zip Code)


                                 (707) 257-2440
                          (Issuer's telephone number)


Check whether the issuer (1) filed all reports required to be filed by Section
13 or 15(d) of the Exchange Act 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
                                   ---        ---


The number of shares of the registrant's Common Stock, no par value, outstanding
as of November 1, 1997, was 776,000.


Transitional Small Business Disclosure Format:

                              Yes         No   X
                                   ---        ---

                                       1
<PAGE>
 
                             NAPA NATIONAL BANCORP
                               TABLE OF CONTENTS


PART I - FINANCIAL INFORMATION

        ITEM 1 - FINANCIAL STATEMENTS

                Balance Sheets:
                        September 30, 1997
                        December 31, 1996

                Statements of Income:
                        Three Months ended September 30, 1997
                        Three Months ended September 30, 1996 
                        Nine Months ended September 30, 1997
                        Nine Months ended September 30, 1996

                Statements of Cash Flows:
                        Nine Months ended September 30, 1997
                        Nine Months ended September 30, 1996


        ITEM 2 - MANAGEMENT'S DISCUSSION AND ANALYSIS OR PLAN OF OPERATION



PART II - OTHER INFORMATION

        ITEM 1 - LEGAL PROCEEDINGS

        ITEM 2 - CHANGES IN SECURITIES AND USE OF PROCEEDS

        ITEM 3 - DEFAULTS UPON SENIOR SECURITIES

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

        ITEM 5 - OTHER INFORMATION

        ITEM 6 - EXHIBITS AND REPORTS ON FORM 8-K


SIGNATURES

INDEX TO EXHIBITS

                                       2
<PAGE>
 
PART I - FINANCIAL INFORMATION


ITEM 1 - FINANCIAL STATEMENTS

The following interim consolidated financial statements of Napa National Bancorp
and its subsidiary Napa National Bank are unaudited and prepared in accordance
with generally accepted accounting principles for interim financial information
and with the instructions to Form 10-QSB. However, they reflect all adjustments
(which included only normal recurring adjustments) which are, in the opinion of
management, necessary for a fair presentation of financial position, results of
operations, and cash flows for the interim periods presented and are normal and
recurring.

Results for the period as presented are not necessarily indicative of results to
be expected of the year as a whole.

                                       3
<PAGE>
 
                     NAPA NATIONAL BANCORP AND SUBSIDIARIES
                          CONSOLIDATED BALANCE SHEETS
                                  (Unaudited)
                               (Dollars in 000's)



<TABLE>
<CAPTION>
                                                  September 30,    December 31,
                                                      1997            1996
                                                      ----            ----
<S>                                               <C>              <C>    
ASSETS
Cash and due from banks                           $     8,005      $     7,929
Federal funds sold                                     17,595           16,550
Time deposits with other financial institutions         3,267            4,158
Investment securities: Held to Maturity                 1,824            1,723
Federal Reserve and Federal Home Loan Bank Stock          582              554
Loans, less allowance for loan losses of $1,530 
     and $1,447 at September 30, 1997 and 
     December 31, 1996                                 83,474           78,290
Premises, furniture, fixtures and equipment,net         2,624            2,519
Accrued interest receivable                               800              647
Other real estate owned                                   607              328
Other assets                                            1,161            1,129
                                                  -----------      -----------
TOTAL ASSETS                                      $   119,939      $   113,827
                                                  ===========      ===========


LIABILITIES AND SHAREHOLDERS' EQUITY
Deposits:
   Non-interest-bearing demand                    $    30,447      $    25,728
   Interest-bearing:
      Savings                                          10,903           11,965
      Transaction                                      31,489           29,317
      Time certificates                                38,014           38,407
                                                  -----------      ----------- 
      Total deposits                                  110,853          105,417
Accrued interest payable and other liabilities            710              439
                                                  -----------      -----------
TOTAL LIABILITIES                                     111,563          105,856
                                                  -----------      -----------

SHAREHOLDERS' EQUITY
Preferred stock, no par value, 1,000,000 shares 
     authorized; no shares outstanding                      0                0
Common stock, no par value, 20,000,000 shares  
     authorized; 776,000 and 754,500 shares 
     issued and outstanding at September 30, 1997 
     and December 31, 1996, respectively                7,086            6,915
Retained earnings                                       1,290            1,056
                                                  -----------      -----------
TOTAL SHAREHOLDERS' EQUITY                              8,376            7,971
                                                  -----------      -----------

TOTAL LIABILITIES AND SHAREHOLDERS' EQUITY        $   119,939      $   113,827
                                                  ===========      ===========
</TABLE>

                                       4
<PAGE>
 
                     NAPA NATIONAL BANCORP AND SUBSIDIARIES
                       CONSOLIDATED STATEMENTS OF INCOME
                                  (Unaudited)
                 (Dollars in 000's, except earnings per share)

<TABLE>
<CAPTION>
                                                       Three Months Ended
                                                          September 30,
                                                      -------------------- 
                                                      1997            1996
                                                      ----            ----
<S>                                               <C>              <C>
Interest income:
     Interest and fees on loans                   $   2,223        $  2,124
     Interest on federal funds sold                     256             136
     Interest on time deposits with other 
       financial institutions                            55              58
     Interest and dividends on investment             
       securities                                        34              27
                                                  ---------        --------
               Total interest income                  2,568           2,345
Interest expense on deposits                            773             703
                                                  ---------        --------
               Net interest income                    1,795           1,642


Provision for loan losses                               102             129
                                                  ---------        --------
               Net interest income after 
                 provision for loan losses            1,693           1,513
                                                  ---------        --------

Non-interest income:
     Service charges on deposit accounts                117              82
     Mortgage loan service fees                          18               2
     Other                                              127             105
                                                  ---------        --------
               Total non-interest income                262             189
                                                  ---------        --------

Non-interest expense:
     Salaries and employee benefits                     811             712
     Occupancy                                          120             120
     Furniture, fixtures and equipment                  121             110
     Other                                              448             350
                                                  ---------        --------
               Total non-interest expense             1,500           1,292
                                                  ---------        --------

               Income before income taxes               455             410

Income taxes                                            184             166
                                                  ---------        --------

               Net income                         $     271        $    244
                                                  =========        ========

Net income per share                              $    0.29        $   0.27
                                                  =========        ========
Weighted average common shares outstanding used 
to compute net income per share                     930,200         903,300
                                                  =========        ========
</TABLE>

                                       5
<PAGE>
 
                     NAPA NATIONAL BANCORP AND SUBSIDIARIES
                       CONSOLIDATED STATEMENTS OF INCOME
                                  (Unaudited)
                 (Dollars in 000's, except earnings per share)
<TABLE>
<CAPTION>
                                                        Nine Months Ended
                                                          September 30,
                                                      --------------------
                                                      1997            1996
                                                      ----            ----
<S>                                               <C>              <C>
Interest income:
     Interest and fees on loans                   $    6,253       $   6,309
     Interest on federal funds sold                      694             360
     Interest on time deposits with other 
       financial institutions                            172             173
     Interest on investment securities                    96              81
                                                  ----------       ---------
               Total interest income                   7,215           6,923
Interest expense on deposits                           2,287           2,087
                                                  ----------       ---------
               Net interest income                     4,928           4,836

Provision for loan losses                                306             308
                                                  ----------       ---------
               Net interest income after 
                 provision for loan losses             4,622           4,528
                                                  ----------       ---------

Non-interest income:
     Service charges on deposit accounts                 310             268
     Mortgage loan service fees                           47              43
     Other                                               371             289
                                                  ----------       ---------
               Total non-interest income                 728             600
                                                  ----------       ---------

Non-interest expense:
     Salaries and employee benefits                    2,495           2,043
     Occupancy                                           345             345
     Furniture, fixtures and equipment                   363             324
     Other                                             1,271           1,031
                                                  ----------       ---------
               Total non-interest expense              4,474           3,743
                                                  ----------       ---------

               Income before income taxes                876           1,385

Income taxes                                             356             561
                                                  ----------       ---------
               Net income                         $      520       $     824
                                                  ==========       =========

Net income per share                              $     0.56       $    0.91
                                                  ==========       =========
Weighted average common shares outstanding used 
to compute net income per share                      927,350         903,300
                                                  ==========       =========
</TABLE>

                                       6
<PAGE>
 
                     NAPA NATIONAL BANCORP AND SUBSIDIARIES
                     CONSOLIDATED STATEMENTS OF CASH FLOWS
                                  (Unaudited)
                               (Dollars in 000's)
<TABLE>
<CAPTION>
                                                        Nine Months Ended
                                                          September 30,
                                                      -------------------- 
                                                      1997            1996
                                                      ----            ----
<S>                                               <C>              <C>
Cash flows from operating activities:
Net income                                        $   520          $   824
Reconciliation of net income to net cash 
  provided by operating activities:
  Depreciation on premises and equipment              358              325
  Amortization of deferred loan fees and 
    discounts/premiums on securities                   21             (396)
  Provision for loan losses                           306              308      
  Gain on sale of other real estate owned             (21)               0
  (Increase) in accrued interest receivable          (153)             (42)
  (Increase) in other assets, net                     (32)            (346)
  Increase(decrease) in accrued interest 
    payable and other liabilities                     271             (205)
                                                  -------          -------
NET CASH PROVIDED BY OPERATING ACTIVITIES           1,270              468
                                                  -------          -------

Cash flows from investing activities:
Loan originations, net of repayments               (5,899)          (4,608)
Proceeds from maturities of time deposits with   
  other financial institutions                        891              198
Activity in securities held to maturity:
  Purchases                                        (1,798)          (2,725)
  Maturities                                        1,697            2,237
Purchases of Federal Reserve and Federal Home    
  Loan Bank stock                                     (28)            (352)
Proceeds from sale of other real estate owned         130                0
Capital expenditures                                 (463)            (349)
                                                  -------          -------
NET CASH (USED) BY INVESTING ACTIVITIES            (5,470)          (5,599)
                                                  -------          -------

Cash flows from financing activities:
Net increase in deposits                            5,436            1,039
Cash dividends                                       (286)            (283)
Exercise of incentive stock options                   171                0 
                                                  -------          -------
NET CASH PROVIDED BY FINANCING ACTIVITIES           5,321              756
                                                  -------          -------

INCREASE IN CASH AND CASH EQUIVALENTS               1,121           (4,375)
 
Cash and cash equivalents at beginning of       
  period                                           24,479           21,886
                                                  -------          -------

Cash and cash equivalents at end of period        $25,600          $17,511
                                                  =======          =======
</TABLE>
(continued)

                                       7
<PAGE>
 
                     NAPA NATIONAL BANCORP AND SUBSIDIARIES
                     CONSOLIDATED STATEMENTS OF CASH FLOWS
                                  (Unaudited)
                               (Dollars in 000's)

<TABLE>
<CAPTION>
                                                        Nine Months Ended
                                                          September 30,
                                                      --------------------
                                                      1997            1996
                                                      ----            ----
<S>                                               <C>              <C>
CASH AND CASH EQUIVALENTS AT SEPTEMBER 30:
   Cash and due from banks                        $  8,005         $  6,881
   Federal funds sold                               17,595           10,630
                                                  --------         --------
                                                  $ 25,600         $ 17,511
                                                  ========         ========
SUPPLEMENTAL CASH FLOW INFORMATION:
   Cash paid for interest                         $  2,413          $ 2,306
   Cash paid for income taxes                           65              815

</TABLE>




                                       8
<PAGE>

ITEM 2 - MANAGEMENT'S DISCUSSION AND ANALYSIS OR PLAN OF OPERATION

Napa National Bancorp (the "Company") was incorporated in 1981 in the State of
California and is headquartered in Napa, California. The Company is a bank
holding company. Its principal subsidiary, Napa National Bank (the "Bank"), was
organized as a national banking association in 1982. The following discussion
and analysis by the Company's management compares the results of the Company's
operations for the nine months ended September 30, 1997 and 1996 and the
financial condition and liquidity of the Company as of September 30, 1997 and
December 31, 1996.

Certain matters discussed in this report are forward-looking statements that are
subject to risks and uncertainties that could cause actual results to differ
materially from those projected in the forward-looking statements. Such risks
and uncertainties include, but are not limited to, the competitive environment
and its impact on the Company's net interest margin, changes in interest rates,
asset quality risks, concentrations of credit and the economic health of Napa
County (particularly the health of the wine industry), volatility of rate
sensitive deposits, asset/liability matching risks, the dilutive impact which
might occur upon the issuance of new shares of common stock, and liquidity
risks. Therefore, the matters set forth below should be carefully considered
when evaluating the Company's business and prospects. For additional information
concerning these risks and uncertainties, please refer to the Company's Annual
Report on Form 10-K for the year ended December 31, 1996

Financial Condition

The Company's assets increased approximately $6.1 million during the first nine
months of 1997 as compared to the period ended December 31, 1996. Total assets
were $119.9 million at September 30, 1997 compared with $113.8 million at
December 31, 1996. Total deposits increased to $110.8 million at September 30,
1997 compared with $105.4 million at December 31, 1996.

The loan portfolio of $85.0 million at September 30, 1997 increased $5.3 million
compared to the December 31, 1996 total of $79.7 million. The allowance for loan
losses on September 30, 1997 was $1,530,000 or 1.80% of total gross loans
outstanding. Net loan charge-offs for the first nine months of 1997 were
$181,000. In the opinion of management, the allowance for loan losses was
considered adequate at September 30, 1997 based on management's analysis of the
risks inherent in the loan portfolio.

The Company's investment portfolio and stock in the Federal Reserve and Federal
Home Loan Bank are classified as "held to maturity securities" in accordance
with SFAS No. 115. At September 30, 1997, the investment portfolio's fair market
value was $1,815,000.

Results of Operations

The Company's after-tax earnings were $520,000 during the first nine months of
1997 compared with $824,000 during the same period in 1996.
 
In February 1997, the Financial Accounting Standards Board issued Statement No.
128, "Earnings Per Share", which is required to be adopted for financial
statements issued for periods ending after December 15, 1997. At that time, the
Company will be required to change the method currently used to compute earnings
per share and to restate all prior periods. Under the new requirements for
calculating primary earnings per share, the dilutive effect of stock options
will be excluded and primary earnings per share will be replaced by basic
earnings per share. The impact is expected to result in an increase in primary
earnings per share for the nine months ended September 30, 1997 and 1996 of
$0.12 and $0.18 per share, respectively. The Company has not yet determined what
the impact of Statement No. 128 will be on the calculation of fully diluted
earnings per share.

Net interest income, the principal source of the Company's earnings, represents
the difference between interest and fees earned from lending and investment
activities and the interest paid on deposits used to fund those activities.
Variations in the volume and mix of loans, investments, and deposits and their
relative sensitivity to movements in interest rates impact net interest income.

                                       9
<PAGE>

During the first nine months of 1997, net interest income at $4,928,000 was
$92,000 ahead of the same period in 1996. The primary cause of the increase was
the growth in Federal Funds Sold income generated through the increase in
deposits. That increase was mitigated by the decrease in loan and fee income for
the first nine months of 1997 of $56,000 as compared to the same period in 1996.
The main reason for the decline, despite an increase in loan volume, was the
early payoff of a loan the Bank had purchased at a premium. At the time of early
payoff, the Bank charged off the remaining balance of the premium. In addition,
non-accrual loans averaged $3.50 million during the first nine months of 1997
compared with $2.1 million in the first nine months of 1996.

Non-interest income increased by $128,000 in the first nine months of 1997. This
increase resulted mainly from a recovery of expenses related to the Main Street
property sold to the County of Napa in 1992.

Non-interest expenses consist of salaries and benefits provided to employees of
the Bank, expenses related to premises and equipment, and operating expenses
associated with the continuing business affairs of the Company. Total
non-interest expenses increased $731,000 or 20% during the first nine months of
1997 when compared with the first nine months of 1996. Salaries and benefits
accounted for $452,000 of this increase as a result of additional employees and
salary increases to existing employees. Other non-interest expense increased
$240,000 for the first nine months of 1997 compared to the same period in 1996,
primarily, as a result of efforts related to collection of problem loans.
 
Capital Resources and Adequacy

Shareholders equity was $8.4 million or 7.0% of total assets at September 30,
1997 compared with $8.0 million or 7.0% of total assets at December 31, 1996.
The ratio of capital to risk-weighted assets at September 30, 1997 was 10.33%
for the Company and 10.31% for the Bank. Both ratios exceeded the regulatory
requirements for a "well-capitalized" institution. Management anticipates that
both the Company and the Bank will continue to exceed the regulatory minimums
for "well-capitalized"institutions in the foreseeable future. Therefore, in
management's opinion, the Company and the Bank have adequate capital in order to
support future growth.

Inflationary Factors

Since the assets and liabilities of the Bank are primarily monetary in nature,
the performance of the Bank is affected more by changes in interest rates than
by inflation.

                                       10
<PAGE>
 
PART II - OTHER INFORMATION

        ITEM 1 - LEGAL PROCEEDINGS
        As of September 30, 1997, the Company was not party to any significant
        legal proceeding.


        ITEM 2 - CHANGES IN SECURITIES AND USE OF PROCEEDS 
        There were no changes in the Company's securities during the quarter.


        ITEM 3 - DEFAULTS UPON SENIOR SECURITIES 
        No securities of this nature.


        ITEM 4 - SUBMISSION OF MATTERS TO A VOTE OF SECURITY HOLDERS 
        On June 17,1997, the Company held an annual meeting of shareholders (the
        "Meeting") for the purpose of (i) electing ten persons to serve as the
        Company's directors until the next annual meeting of shareholders and
        until their respective successors shall be elected and qualified, and
        (ii) ratifying the appointment of Ernst & Young LLP as the Company's
        independent public accountants for the 1997 fiscal year.

        All ten of management's nominees for directors were elected at the
        Meeting, and there was no opposition to management's nominees as listed
        in the Company's proxy statement first mailed to shareholders on April
        30, 1997. The number of votes cast for and against, and the number of
        abstentions and broker non-votes relating to, each of management's
        nominees is set forth below:

                                                                Abstentions and
        Name                            For         Against     Broker Non-Votes
        ----                            ---         -------     ----------------

        William A. Bacigalupi           562,285     1,525       198,190
        Dennis Groth                    562,285     1,525       198,190
        E. James Hedemark               562,185     1,625       198,190
        Michael D. Irwin                562,185     1,625       198,190
        Brian J. Kelly                  562,510     1,300       198,190
        C. Richard Lemon                562,003     1,807       198,190
        Joseph G. Peatman               561,185     2,625       198,190
        A. Jean Phillips                561,510     2,300       198,190
        George M. Schofield             562,510     1,300       198,190
        W. Clarke Swanson, Jr.          562,410     1,400       198,190
                                                
        The appoinment of Ernst & Young LLP as the Company's independent public
        accountants for the 1997 fiscal year was ratified by a majority vote of
        the Company's shareholders. 562,610 votes were cast in favor of
        ratification, 400 votes were cast against, and there were 800
        abstentions and broker non-votes.

                                       11
<PAGE>
 
        ITEM 5 - OTHER INFORMATION 
        None.


        ITEM 6 - EXHIBITS AND REPORTS ON FORM 8-K

        (a) Exhibits. See Index to Exhibits to this Form 10-SBQ, for a list of
        the exhibits filed as a part of this report and incorporated herein by
        reference.

        (b)     Reports on Form 8-K:

        The Company did not file a report on Form 8-K during the third quarter 
        of 1997.

                                       12
<PAGE>
 
SIGNATURES

In accordance with the requirements of the Exchange Act, the Registrant has
caused this report to be signed on its behalf by the undersigned, thereunto duly
authorized.


                                                       NAPA NATIONAL BANCORP
                                                           (Registrant)




Date: November 14, 1997                                /s/ Brian J. Kelly
                                                       ------------------
                                                       Brian J. Kelly
                                                       President / COO



Date: November 14, 1997                                /s/ Michael D. Irwin
                                                       --------------------
                                                       Michael D. Irwin
                                                       Chief Financial Officer

                                       13
<PAGE>
 
                               INDEX TO EXHIBITS

EXHIBIT NO.                       DESCRIPTION

3(i)*           Articles of Incorporation of the Registrant, as amended.

3(ii)*          Restated Bylaws of the Registrant.

4.1*            A specimen copy of the certificates evidencing Common Stock.

10.1*           Napa National Bancorp 1992 Stock Option Plan.

10.2*           Form of Incentive Stock Option Agreement.

10.3*           Form of Nonstatutory Stock Option Agreement.

27              Financial Data Schedule.


*Previously filed.

                                       14