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                                                              Exhibit EX-99.CERT

                                 CERTIFICATIONS

I, Joseph A. Varnas, President of UBS Municipal Money Market Series, certify
that:

1.     I have reviewed this report on Form N-CSR of UBS Municipal Money Market
       Series;

2.     Based on my knowledge, this report does not contain any untrue statement
       of a material fact or omit to state a material fact necessary to make the
       statements made, in light of the circumstances under which such
       statements were made, not misleading with respect to the period covered
       by this report;

3.     Based on my knowledge, the financial statements, and other financial
       information included in this report, fairly present in all material
       respects the financial condition, results of operations, changes in net
       assets, and cash flows (if the financial statements are required to
       include a statement of cash flows) of the registrant as of, and for, the
       periods presented in this report;

4.     The registrant's other certifying officer(s) and I are responsible for
       establishing and maintaining disclosure controls and procedures (as
       defined in Rule 30a-3(c) under the Investment Company Act of 1940) for
       the registrant and have:

            (a)  Designed such disclosure controls and procedures, or caused
                 such disclosure controls and procedures to be designed under
                 our supervision, to ensure that material information relating
                 to the registrant, including its consolidated subsidiaries, is
                 made known to us by others within those entities, particularly
                 during the period in which this report is being prepared;

            (b)  Evaluated the effectiveness of the registrant's disclosure
                 controls and procedures and presented in this report our
                 conclusions about the effectiveness of the disclosure controls
                 and procedures, as of a date within 90 days prior to the filing
                 date of this report based on such evaluation; and

            (c)  Disclosed in this report any change in the registrant's
                 internal control over financial reporting that occurred during
                 the second fiscal quarter of the period covered by this report
                 that has materially affected, or is reasonably likely to
                 materially affect, the registrant's internal control over
                 financial reporting; and

5.     The registrant's other certifying officer(s) and I have disclosed to the
       registrant's auditors and the audit committee of the registrant's board
       of directors (or persons performing the equivalent functions):

            (a)  All significant deficiencies and material weaknesses in the
                 design or operation of internal control over financial
                 reporting which are reasonably likely to adversely affect the
                 registrant's ability to record, process, summarize, and report
                 financial information; and

            (b)  Any fraud, whether or not material, that involves management or
                 other employees who have a significant role in the registrant's
                 internal control over financial reporting.

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By:    /s/ Joseph A. Varnas
       --------------------
       Joseph A. Varnas
       President

Date:  March 9, 2005
       -------------


I, Thomas Disbrow, Treasurer of UBS Municipal Money Market Series, certify that:

1.     I have reviewed this report on Form N-CSR of UBS Municipal Money Market
       Series;

2.     Based on my knowledge, this report does not contain any untrue statement
       of a material fact or omit to state a material fact necessary to make the
       statements made, in light of the circumstances under which such
       statements were made, not misleading with respect to the period covered
       by this report;

3.     Based on my knowledge, the financial statements, and other financial
       information included in this report, fairly present in all material
       respects the financial condition, results of operations, changes in net
       assets, and cash flows (if the financial statements are required to
       include a statement of cash flows) of the registrant as of, and for, the
       periods presented in this report;

4.     The registrant's other certifying officer(s) and I are responsible for
       establishing and maintaining disclosure controls and procedures (as
       defined in Rule 30a-3(c) under the Investment Company Act of 1940) for
       the registrant and have:

            (a)  Designed such disclosure controls and procedures, or caused
                 such disclosure controls and procedures to be designed under
                 our supervision, to ensure that material information relating
                 to the registrant, including its consolidated subsidiaries, is
                 made known to us by others within those entities, particularly
                 during the period in which this report is being prepared;

            (b)  Evaluated the effectiveness of the registrant's disclosure
                 controls and procedures and presented in this report our
                 conclusions about the effectiveness of the disclosure controls
                 and procedures, as of a date within 90 days prior to the filing
                 date of this report based on such evaluation; and

            (c)  Disclosed in this report any change in the registrant's
                 internal control over financial reporting that occurred during
                 the second fiscal quarter of the period covered by this report
                 that has materially affected, or is reasonably likely to
                 materially affect, the registrant's internal control over
                 financial reporting; and

5.     The registrant's other certifying officer(s) and I have disclosed to the
       registrant's auditors and the audit committee of the registrant's board
       of directors (or persons performing the equivalent functions):

            (a)  All significant deficiencies and material weaknesses in the
                 design or operation of internal control over financial
                 reporting which are reasonably likely to adversely affect the
                 registrant's ability to record, process, summarize, and report
                 financial information; and

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            (b)  Any fraud, whether or not material, that involves management or
                 other employees who have a significant role in the registrant's
                 internal control over financial reporting.


By:    /s/ Thomas Disbrow
       ------------------
       Thomas Disbrow
       Treasurer

Date:  March 9, 2005
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