<PAGE>

                                                                    EXHIBIT 10.1

                                  June 21, 2002


        Mr. Ralph Rubio
        President, CEO
        Rubio's Restaurants, Inc.
        1902 Wright Place, Suite 300
        Carlsbad, CA 92008

        Re:  Amendment to Beverage Marketing Agreement dated March 6, 1998

        Dear Mr. Rubio:

        This letter will constitute an amendment (the "Amendment") to the Term
        Sheet between Coca-Cola Fountain ("CCF") and Rubio's Restaurants, Inc.
        ("Rubio's") dated March 6, 1998 (the "Agreement"). The capitalized terms
        contained in this Amendment will have the same meaning set forth in the
        Agreement unless otherwise defined in this Amendment.

        In addition,                  ***
                                      ***
                                      ***

        Effective June 1, 2002 (the "Effective Date"), the Agreement is amended
        as follows:

        TERM

        The first sentence of the Term section is modified by extending the Term
        until the later of: (i) June 1, 2012 or (ii) when Rubio's has purchased
        its Volume Commitment of CCF's Fountain Syrups.

        BEVERAGE AVAILABILITY

        The second sentence of the second paragraph of the Beverage Availability
        section is modified as follows:

                CCF's Fountain Beverages will be the only Fountain Beverages
                served in the Covered Outlets, except for adult frozen "fancy
                cocktails" (e.g., margarita-type drinks).

        The third paragraph of the Beverage Availability section is modified as
        follows:






        *** Portions of this page have been omitted pursuant to a request for
            Confidential Treatment and filed separately with the Commission.
<PAGE>

Mr. Ralph Rubio
June 21, 2002
Page 2


                Rubio's recognizes that the sale of competitive Beverage in
                bottles, cans or other packaging would diminish the product
                availability rights given to CCF, and therefore also agrees not
                to serve competitive Beverages in bottles, cans in the Covered
                Outlets, except for bottled water. Under no circumstances will
                Rubio's serve any product of PepsiCo in the Covered Outlets.

        The following paragraph is added at the end of the Beverage Availability
        section:

                Except as specifically provided in this Beverage Availability
                section, Rubio's agrees that it shall be in compliance with the
                Beverage Availability section upon the expiration of its
                pre-existing agreements with unaffiliated third parties and
                suppliers of competitive Beverages. In particular, Rubio's
                agrees that Dr. Pepper(R) will not be served in its Covered
                Outlets after April 30, 2003. In addition, Rubio's agrees that
                during the first year of the Term it will conduct tests of
                Dasani(R) bottled water, Nestea(R) tea, and CCF's frozen
                Beverage mixers. Such tests will be conducted according to
                mutually agreed upon test parameters (including duration of test
                and test performance criteria) that will be established in
                advance of the introduction to determine the success or failure
                of the tests. In conducting such tests, Rubio's agrees that it
                will provide sales data to CCF at the end of every four-weeks
                during the test period that will be used to measure the results
                of the test. CCF and Rubio's will mutually analyze and evaluate
                the sales data to meet mutually agreed upon sales criteria and
                to mutually determine the success of the tests.

        VOLUME COMMITMENT

        The Volume Commitment section is deleted in its entirety and substituted
        with the following language:

        Rubio's agrees that, beginning June 1, 2002 until the end of the Term,
        the Covered Outlets will purchase an additional *** of CCF's Fountain
        Syrups. Accordingly, the total Volume Commitment is *** of CCF's
        Fountain Syrups.

        MARKETING PROGRAM

        CONVERSION FUND.

        The following sentence is added at the end of the Conversion Fund
        subsection:

                *** conversion from Dr. Pepper(R) to CCF's brands, CCF will pay
                funding in the amount of *** (the "Incremental Conversion


--------

*** Portions of this page have been omitted pursuant to a request for
Confidential Treatment and filed separately with the Commission.

<PAGE>

Mr. Ralph Rubio
June 21, 2002
Page 3


                Fund"). In the event that Rubio's elects to serve CCF's
                Nestea(R) tea in all of the Covered Outlets instead of brewed
                tea, CCF will provide additional funding in the amount of *** to
                offset the costs of such conversion (the "Tea Conversion Fund").
                Tea Conversion funding will be paid *** .

        PROMOTIONAL SUPPORT FUND.

        A new "Promotional Support Fund" subsection is added at the end of the
        Marketing Program section as follows:

                PROMOTIONAL SUPPORT FUND. Beginning in January of calendar year
                2003 through and including January of calendar year 2012, CCF
                shall pay Rubio's an *** Promotional Support Fund payment of ***
                to offset the cost of the following activities. To qualify for
                funding, each Covered Outlet will comply with a minimum of ***
                of the following performance criteria:

                      1.   Conduct *** a minimum of *** crew incentive and
                           training program designed to increase the sale of
                           CCF's Fountain Beverages in the Covered Outlets; and

                      2.   Conduct tests of Dasani(R) bottled water,
                           Nestea(R)tea, and CCF's frozen Beverage mixers as
                           detailed in the Beverage Availability Section above;
                           and

                      3.   Perform those additional marketing activities that
                           involve CCF's Fountain Beverages that the parties
                           mutually agree upon.

        NESTEA(R) TEA BRAND BUILDING FUND.

        A new "Nestea(R) Tea Brand Building Fund" subsection is added at the end
        of the Marketing Program section as follows:

                NESTEA(R) TEA BRAND BUILDING FUND. In the event that Rubio's
                serves Nestea(R) Fountain Beverage in all of its Covered
                Outlets, beginning in January of calendar year following such
                conversion through and including January of calendar year 2012,
                CCF shall pay Rubio's an *** Nestea(R) Tea Brand Building Fund
                payment of *** . To qualify for funding, each Covered Outlet
                will comply with *** of the following performance criteria:


--------

*** Portions of this page have been omitted pursuant to a request for
Confidential Treatment and filed separately with the Commission.

<PAGE>

Mr. Ralph Rubio
June 21, 2002
Page 4


                      1.   Execute a minimum of *** merchandising activity
                           and/or promotional activity *** that is designed to
                           increase the sale of CCF's Nestea(R) Fountain
                           Beverage in the Covered Outlets; and

                      2.   Perform those additional marketing activities that
                           involve CCF's Nestea(R) Fountain Beverages that the
                           parties mutually agree upon.

        BUSINESS BUILDING FUND.

        A new "Business Building Fund" subsection is added immediately after the
        end of the Nestea(R) Brand Building Fund subsection as follows:

                BUSINESS DEVELOPMENT FUND. *** execution of this Agreement, CCF
                shall make a *** in the amount of *** and in *** , CCF shall
                make another *** of *** . These *** are to offset the costs of
                conducting a minimum of *** of the following activities that
                Rubio's will conduct in the Covered Outlets throughout the Term:

                1.   Execute mutually agreed upon strategies that are designed
                     to increase combo meal incidence in the Covered Outlets;
                     and

                2.   Mutually agreed upon marketing and/or promotional
                     activities that are designed to increase Fountain Beverage
                     transactions in the Covered Outlets; and

                3.   Those additional business development activities that the
                     parties mutually agree upon.

        EQUIPMENT PROGRAM

        The following sentence is added after the first sentence of the
        Equipment Program section:

                In the event Rubio's elects to serve CCF's Nestea(R) Fountain
                Beverages in all of the Covered Outlets, CCF also will provide
                without charge one tea urn per Covered Outlet.

        TERMINATION

        The Termination section is modified by adding the following sentences at
        the end of the first bullet point of the third sentence:


--------

*** Portions of this page have been omitted pursuant to a request for
Confidential Treatment and filed separately with the Commission.

<PAGE>

Mr. Ralph Rubio
June 21, 2002
Page 5


                Incremental Conversion Fund will be earned at the rate of ***
                per gallon; Tea Conversion Fund, Promotional Support Funds and
                Nestea(R) Brand Building Fund will be earned at the rate of ***
                per month; and Business Development Funds will be earned at the
                rate of *** per gallon.

        If this letter conforms to our agreement, please sign the enclosed copy
        and return it to me for my files. By signing this Amendment, you
        represent and warrant that you are authorized to enter into contracts on
        behalf of Rubio's governing the subject matter of this Amendment.

                                        Sincerely,

                                        /s/ Dan Manning
                                        Dan Manning
                                        Vice President, West Group
                                        Coca-Cola Fountain

        Agreed to this _______ day of June, 2002.

        RUBIO'S RESTAURANTS, INC.

        By:  /s/ Ralph Rubio
            -------------------------
            Mr. Ralph Rubio
            President, CEO


--------

*** Portions of this page have been omitted pursuant to a request for
Confidential Treatment and filed separately with the Commission.