Filed Pursuant to Rule 424(b)(1)
                                                     Registration No. 333-61679
 
                                400,000 Shares
 
                              GREATER BAY BANCORP
 
                                 COMMON STOCK
 
                                (NO PAR VALUE)
 
                               ----------------
 
  The Leo K.W. Lum PRB Revocable Trust (the "Selling Stockholder") is offering
and selling 400,000 shares of Greater Bay Bancorp ("GBB," the "Company" or
"Greater Bay") Common Stock (the "Shares") under this Prospectus. The Selling
Stockholder acquired the Shares on May 8, 1998 by virtue of the merger of
Pacific Rim Bancorporation ("PRB") into the Company. As a result of the
merger, Golden Gate Bank ("GGB"), formerly a subsidiary of PRB, is now a
wholly owned subsidiary of the Company. See "Selling Stockholder." The Selling
Stockholder may offer its Shares through public or private transactions
through Nasdaq or otherwise, at prevailing market prices, or at privately
negotiated prices.
 
  The Common Stock is quoted on the Nasdaq National Market under the symbol
"GBBK." The last sale price for the Common Stock on August 20, 1998, as
reported on the Nasdaq National Market System, was $31.00 per share. The
Company will pay any fees and expenses of registering the Shares, including
registering the sale of the Shares in any state, if necessary, but will not
pay commissions or other selling expenses or any stock transfer taxes. The
fees and expenses for registration of the Shares are estimated to be $36,983.
 
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  SEE "RISK FACTORS," BEGINNING ON PAGE 3, FOR A DISCUSSION OF CERTAIN FACTORS
THAT SHOULD BE CONSIDERED BY PROSPECTIVE PURCHASERS OF THE COMMON STOCK
OFFERED HEREBY.
 
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 THESE SECURITIES HAVE NOT BEEN APPROVED OR DISAPPROVED BY THE SECURITIES AND
  EXCHANGE  COMMISSION  OR  ANY  STATE SECURITIES  COMMISSION  NOR  HAS  THE
   COMMISSION OR ANY  STATE SECURITIES COMMISSION PASSED  UPON THE ACCURACY
    OR ADEQUACY OF THIS PROSPECTUS.  ANY REPRESENTATION TO THE CONTRARY IS
     A CRIMINAL OFFENSE.
 
  The Selling Stockholder and any such brokers or dealers may be deemed to be
"underwriters" within the meaning of the Securities Act of 1933, as amended
(the "Securities Act"), and any discounts, concessions and commissions
received by any such brokers and dealers may be deemed to be underwriting
commissions or discounts under the Securities Act. The Company will not
receive any of the proceeds from any sale of the Shares offered hereby. See
"Use of Proceeds," "Selling Stockholder" and "Plan of Distribution."
 
                               ----------------
 
                THE DATE OF THIS PROSPECTUS IS AUGUST 21, 1998

 
                      WHERE YOU CAN FIND MORE INFORMATION
 
  We file annual, quarterly and special reports, proxy statements and other
information with the SEC. You may read and copy any document we file at the
SEC's public reference rooms in Washington, D.C., New York, New York and
Chicago, Illinois. Please call the SEC at 1-800-SEC-0330 for further
information on the public reference rooms. Our SEC filings are also available
to the public from the SEC's Website at "http://www.sec.gov."
 
  The SEC allows us to "incorporate by reference" the information we file with
them, which means that we can disclose important information to you by
referring you to those documents. The information incorporated by reference is
considered to be part of this prospectus, and information that we file later
with the SEC will automatically update and supersede this information. We
incorporate by reference the documents listed below and any future filings we
will make with the SEC under Sections 13(a), 13(c), 14 or 15(d) of the
Securities Exchange Act of 1934:
 
    1. The Company's Annual Report on Form 10-K for the fiscal year ended
  December 31, 1997.
 
    2. The Company's Quarterly Reports on Form 10-Q for the fiscal quarters
  ended June 30, 1998, and March 31, 1998.
 
    3. The Company's Current Reports on Form 8-K dated May 20, 1998 and July
  17, 1998.
 
    4. The description of the Common Stock contained in the Company's
  Registration Statement on Form 8-A filed with the Commission under the
  Exchange Act.
 
  You may request a copy of these filings, at no cost, by writing Investor
Relations Department, Greater Bay Bancorp, 2860 West Bayshore Road, Palo Alto,
California 94303, or by calling (650) 813-8200.
 
  This Prospectus is part of a Registration Statement we filed with the SEC.
You should rely only on the information or representations provided in this
Prospectus. We have authorized no one to provide you with different
information. We are not making an offer of these securities in any state where
the offer is not permitted. You should not assume that the information in this
Prospectus is accurate as of any date other than the date on the front of the
document.
 
                          FORWARD-LOOKING STATEMENTS
 
  This Prospectus contains forward-looking statements within the meaning of
Section 27A of the Securities Act and Section 21E of the Exchange Act,
including statements regarding the Company's financing needs, business plans
and prospects, expectations and intentions. Forward-looking statements
necessarily involve risks and uncertainties, and the Company's actual results
could differ materially from those anticipated in these forward-looking
statements as a result of certain factors, including those set forth below and
elsewhere in this Prospectus. The factors set forth below under "Risk Factors"
and other cautionary statements made in this Prospectus should be read and
understood as being applicable to all related forward-looking statements
wherever they appear in this Prospectus.
 
                                       2

 
                                    SUMMARY
 
  Greater Bay is a bank holding company with operating subsidiaries Cupertino
National Bank ("CNB"), Mid-Peninsula Bank ("MPB"), Peninsula Bank of Commerce
("PBC") and GGB (CNB, MPB, PBC and GGB collectively being referred to as the
"Banks") with ten regional offices in Cupertino, Millbrae, Palo Alto, Redwood
City, San Bruno, San Mateo, San Jose and San Francisco, California. In
addition, Greater Bay, through CNB, operates Greater Bay Trust Company and
Venture Banking Group as separate operating divisions.
 
                              RECENT DEVELOPMENTS
 
  On August 4, 1998, Greater Bay entered into an agreement to acquire Pacific
Business Funding Corporation ("PBFC"), an asset-based speciality finance
company. The acquisition is structured as a merger transaction in which Greater
Bay will acquire PBFC as a wholly owned subsidiary, in consideration of the
issuance of approximately 264,000 shares of Greater Bay common stock to the
shareholders of PBFC. PBFC had total assets of approximately $14.9 million as
of May 31, 1998. It is anticipated that the transaction will be accounted for
as a pooling-of-interests. In connection with the transaction, Greater Bay may
obtain a line of credit in the aggregate principal amount of up to $10.0
million to enable PBFC to repay its existing line of credit. The line of credit
which Greater Bay may obtain would constitute Senior Indebtedness. The
transaction is expected to close on or before August 31, 1998.
 
  In addition, consistent with the Company's operating philosophy and growth
strategy, the Company recently announced that it has formed the Greater Bay
Bank Santa Clara Valley Commercial Banking Group and established an
International Banking Division.
 
                                  RISK FACTORS
 
ABILITY OF THE COMPANY TO EXECUTE ITS BUSINESS STRATEGY
 
  The Company's financial performance and profitability will depend on its
ability to execute its business strategy and manage its recent and possible
future growth. The Company has acquired several Banks in recent years and,
although the Company believes that it has substantially integrated the business
and operations of the Banks into the Company, unforeseen issues relating to the
assimilation of these Banks may adversely affect the Company. In addition,
future acquisitions or other possible future growth may present operating and
other problems that could adversely affect the Company's business, financial
condition and results of operations. The Company's financial performance will
also depend on the Company's ability to maintain profitable operations through
implementation of its Super Community Banking Philosophy, described in the 10-
K. Accordingly, the Company cannot guarantee that it will be able to continue
the growth or maintain the level of profitability it has recently experienced.
 
INTEREST RATE RISK
 
  The Company's earnings depend largely on the relationship between the cost of
funds, primarily deposits, and the yield on earning assets. This relationship,
known as the interest rate spread, may fluctuate and is affected by economic
and competitive factors which influence interest rates, the volume and mix of
interest-earning assets and interest-bearing liabilities, and the level of non-
performing assets. Fluctuations in interest rates affect the demand of
customers for the Company's products and services. The Company is affected by
interest rate risk to the extent that its interest-bearing liabilities reprice
or mature more slowly or more rapidly or on a different basis than its
interest-earning assets. Given the
 
                                       3

 
Company's current volume and mix of interest-bearing liabilities and interest-
earning assets, the Company's interest rate spread may increase during times of
rising interest rates and, conversely, may decline during times of falling
interest rates. Although the Company believes its current level of interest
rate sensitivity is reasonable, significant fluctuations in interest rates may
adversely affect the Company's results of operations.
 
ECONOMIC CONDITIONS AND GEOGRAPHIC CONCENTRATION
 
  The Company's operations are located in Northern California and concentrated
solely in San Francisco, Santa Clara and San Mateo Counties, which include the
area known as the "Silicon Valley." Due to its geographic concentration, the
Company is affected by economic conditions in these areas. A deterioration in
those economic conditions, particularly in the technology and real estate
industries on which these areas depend, could cause more delinquencies and
problems in repayment of the Company's loans or reduce demand for its products
and services, which would adversely affect its earnings.
 
GOVERNMENT REGULATION AND MONETARY POLICY
 
  The banking industry is closely regulated by various federal and state
agencies. Such regulation limits the way that Greater Bay and the Banks conduct
their respective businesses, undertake new investments and activities and
obtain financing. This regulation is designed primarily for the protection of
the deposit insurance funds and consumers, and not to benefit holders of the
Company's securities. Financial institution regulation has been the subject of
significant legislation in recent years, and may be the subject of further
significant legislation in the future, none of which is in the control of the
Company. Significant new laws or changes in, or repeals of, existing laws may
materially affect the Company's results. Further, federal monetary policy,
particularly as implemented through the Federal Reserve System, significantly
affects credit conditions for the Company, primarily through open market
operations in United States government securities, the discount rate for bank
borrowings and bank reserve requirements, and a material change in these
conditions would be likely to materially impact the Company's results of
operations.
 
COMPETITION
 
  The banking and financial services industry in California, as well as the
rest of the United States, is highly and increasingly competitive. The Banks
compete for client loans, deposits and other financial products and services
with other commercial banks, savings and loan associations, securities and
brokerage companies, mortgage companies, insurance companies, finance
companies, money market and other mutual funds, credit unions, and other non-
bank financial services providers. Many of these competitors are much larger in
total assets and capitalization, have greater access to capital markets and
offer a broader array of financial products and services than the Banks. This
competitive environment has resulted from changes in regulation, changes in
technology and product delivery systems, and the consolidation among financial
services providers. In order to compete with other financial services
providers, the Banks principally depend upon promotional activities and
industry knowledge in its market areas, personal relationships with clients and
other service providers, referral sources established by officers, directors
and employees, and specialized services tailored to meet the Banks' clients'
needs. If the Banks are unable to accommodate a client's needs, the Banks will
seek to arrange for those services to be provided by their network of
correspondents and other service providers.
 
CREDIT QUALITY
 
  A significant source of risk for the Company arises from the possibility that
losses will be sustained because borrowers, guarantors and related parties may
fail to perform in accordance with the terms of
 
                                       4

 
their loans. The Company has adopted underwriting and credit monitoring
procedures and credit policies, including the establishment and review of the
allowance for credit losses, that management believes are appropriate to
minimize this risk by assessing the likelihood of nonperformance, tracking loan
performance and diversifying the Company's credit portfolio. Such policies and
procedures, however, may not prevent unexpected losses that could materially
adversely affect the Company's results of operations.
 
YEAR 2000 COMPLIANCE
 
  The "Year 2000" issue is the result of computer programs and equipment which
are dependent on "embedded chip technology" using two digits rather than four
to define the applicable year. Any of the Company's computer programs or
equipment that are date dependent may recognize a date using "00" as the year
1900 rather than the year 2000. This could result in a system failure or
miscalculations causing various problems including disruptions of operations, a
temporary inability to process transactions, send invoices, or engage in
similar normal business activity. Based on assessments made to date, the
Company has determined that it may be required to modify or replace portions of
its software and other equipment so that its computer, security and
communications systems will properly utilize dates beyond December 31, 1999.
The Company believes that with modifications or conversions of software, and
replacement of equipment which cannot be made Year 2000 compliant, the Year
2000 issue can be mitigated. If such modifications, conversions or equipment
replacements are not made, or are not completed in a timely manner, the Year
2000 issue could have a material adverse impact on the Company's operations. In
addition to issues relating to internal Year 2000 compliance, the Company
depends on third party suppliers and large customers to remedy their own Year
2000 Issue. There can be no guarantee that the systems of other companies on
which the Company's systems rely will be timely converted, or that a failure to
convert by another company, or a conversion that is incompatible with the
Company's system, would not have a material adverse effect on the Company.
 
OTHER RISK FACTORS
 
  For a discussion of other risk factors that should be considered by potential
investors, please see the sections entitled "Business" and "Management's
Discussion and Analysis of Financial Condition and Results of Operations" in
Greater Bay's Annual Report on Form 10-K for the year ended December 31, 1997
which is incorporated herein by reference.
 
                                USE OF PROCEEDS
 
  The Selling Stockholder will receive all of the net proceeds from the sale of
the Shares. None of the proceeds will be available for the Company's use or
benefit.
 
                                       5

 
                              SELLING STOCKHOLDER
 
  Under a Registration Rights Agreement dated as of May 8, 1998 between the
Company and the Selling Stockholder (the "Registration Rights Agreement"), we
agreed to register the Shares and to use our best efforts to keep the
Registration Statement effective until May 8, 1999, or until all of the
registered Shares are sold under the Registration Statement, whichever comes
first, subject to certain conditions and limitations. Our registration of the
Shares does not necessarily mean that the Selling Stockholder will sell all or
any of the Shares. The following table shows certain information regarding the
shares owned by the Selling Stockholder as of July 31, 1998. The Company
believes the Selling Stockholder has sole voting and investment power over the
Shares.
 
  The Shares being sold by the Selling Stockholder were received by the Leo
K.W. Lum PRB Revocable Trust in connection with the acquisition of GGB
consummated on May 8, 1998. Mr. Lum was an officer, director and the sole
shareholder of PRB, the former holding company of GGB. Mr. Lum became a
director of the Company on May 26, 1998.
 


                              SHARES OWNED PRIOR             SHARES OWNED AFTER
                                 TO OFFERING       NUMBER OF      OFFERING
                             --------------------- SHARES TO ------------------
            NAME              NUMBER    PERCENTAGE  BE SOLD  NUMBER  PERCENTAGE
            ----             ---------  ---------- --------- ------- ----------
                                                      
The Leo K.W. Lum PRB
Revocable Trust
344 Pine Street
San Francisco, CA 94104..... 950,748(1)    10.3%    400,000  550,748    5.9%

 
- --------
(1) All of the 950,748 shares of Greater Bay Bancorp Common Stock owned of
    record by the Leo K.W. Lum PRB Revocable Trust are owned beneficially by
    Mr. Leo K.W. Lum.
 
                             PLAN OF DISTRIBUTION
 
  The Selling Stockholder may offer the Shares at various times in one or more
of the following transactions:
 
    . on Nasdaq National Market;
 
    . in the over-the-counter market;
 
    . in transactions other than in the over-the-counter market;
 
    . in connection with short sales of the Shares;
 
    . by pledge to secure debts and other obligations;
 
    . in connection with the writing of non-traded and exchange-traded call
  options, in hedge transactions and in settlement of other transactions in
  standardized or over-the-counter options; or
 
    . in a combination of any of the above transactions.
 
  The Selling Stockholder may sell the Shares at market prices prevailing at
the time of sale, at prices related to such prevailing market prices, at
negotiated prices or at fixed prices.
 
  The Selling Stockholder may use broker-dealers to sell the Shares. If this
happens, broker-dealers will either receive discounts or commissions from the
Selling Shareholder, or they will receive commissions from purchasers of
shares for whom they acted as agents. The Company may agree to indemnify
participating brokers or dealers against certain civil liabilities, including
liabilities under the Securities Act.
 
  The Selling Stockholder and any such brokers or dealers may be deemed to be
"underwriters" within the meaning of the Securities Act, in which case any
discounts, commissions or concessions received by such brokers or dealers and
any profit on the resale of the Shares purchased by such brokers or dealers
may be deemed to be underwriting commissions or discounts under the Securities
Act.
 
                                       6

 
  Any Shares covered by this Prospectus which qualify for sale pursuant to
Rule 144 under the Securities Act may be sold under Rule 144 rather than
pursuant to this Prospectus. The Selling Stockholder may not sell any or all
of the Shares. The Selling Stockholder may transfer, devise or gift such
Shares by other means not described herein. Under the Registration Rights
Agreement, the Selling Stockholder agreed to limit the number of Shares and
other Company securities sold during any three month period to an amount equal
to the greater of 1% of the outstanding Common Stock or the average weekly
trading volume of trading in the Common Stock during the four preceding
calendar weeks.
 
  The Company will pay any fees and expenses of registering the Shares,
including registering the sale of the Shares in any state, if necessary, but
will not pay commissions or other selling expenses or any stock transfer
taxes.
 
  The Company has informed the Selling Stockholder that the anti-manipulation
provisions of Regulation M under the Exchange Act may apply to its sales of
the Shares and has furnished the Selling Stockholder with a copy of these
rules. The Company has also advised the Selling Stockholder of the requirement
for delivery of this Prospectus in connection with any public sale of the
Shares.
 
                           VALIDITY OF COMMON STOCK
 
  The law firm of Manatt, Phelps & Phillips, LLP, Los Angeles, California,
will give its opinion on the legality of the Shares, for the purpose of this
offering.
 
                                    EXPERTS
 
  The consolidated balance sheets as of December 31, 1997 and 1996 and the
consolidated statements of operations, shareholders' equity and cash flows for
each of the three years in the period ended December 31, 1997 incorporated by
reference in this Registration Statement, have been incorporated herein in
reliance on the report of PricewaterhouseCoopers LLP, independent accountants,
given on the authority of that firm as experts in accounting and auditing.
 
                                       7

 
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 YOU SHOULD RELY ONLY ON THE INFORMATION OR REPRESENTATIONS PROVIDED IN THIS
PROSPECTUS. WE HAVE AUTHORIZED NO ONE TO PROVIDE YOU WITH DIFFERENT INFORMA-
TION. WE ARE NOT MAKING AN OFFER OF THESE SECURITIES IN ANY STATE WHERE THE
OFFER IS NOT PERMITTED. YOU SHOULD NOT ASSUME THAT THE INFORMATION IN THIS
PROSPECTUS IS ACCURATE AS OF ANY DATE OTHER THAN THE DATE ON THE FRONT OF THE
DOCUMENT.
 
 
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                               TABLE OF CONTENTS
 


                                                                            PAGE
                                                                            ----
                                                                         
Where You Can Find More Information........................................   2
Forward-Looking Statements.................................................   2
Summary....................................................................   3
Recent Developments........................................................   3
Risk Factors...............................................................   3
Use of Proceeds............................................................   5
Selling Stockholder........................................................   6
Plan of Distribution.......................................................   6
Validity of Common Stock...................................................   7
Experts....................................................................   7

 
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                                400,000 Shares
 
                              GREATER BAY BANCORP
 
                                    [LOGO]
 
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                                  PROSPECTUS
 
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                                August 21, 1998
 
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