Putnam Investments
                                                  One Post Office Square
                                                  Boston, MA 02109
                                                  February 6, 2001


Securities and Exchange Commission
450 Fifth Street, N.W.
Washington, DC  20549

RE: Putnam Money Market Fund (Reg. No. 2-55091) (811-2608)
    Post-Effective Amendment No. 31 to Registration Statement on Form N-1A

    Putnam Tax Exempt Money Market Fund (Reg. No. 33-15238) (811-5215)
    Post-Effective Amendment No. 15 to Registration Statement on Form N-1A

Ladies and Gentlemen:

     Pursuant to Rule 497(j) under the Securities Act of 1933, as amended,
Putnam Money Market Fund and Putnam Tax Exempt Money Market Fund ("the
Funds") hereby certify that the form of Prospectuses and Statement of
Additional Information that would have been filed on behalf of the Funds
pursuant to Rule 497(c) upon the effectiveness of Post-Effective
Amendment No. 31 and No.15 to the Registration Statements on Form N-1A
(the "Amendments") for Putnam Money Market Fund and Putnam Tax Exempt
Money Market Fund , respectively, would not have differed from that
contained in the Amendments, which are the most recent amendments to
such Registration Statements and were filed electronically on January
30, 2001.

     Comments or questions concerning this certificate may be directed to
Beth Werths at 1-800-225-2465, ext. 1-1913.

                                     Very truly yours,

                                     Putnam Money Market Fund and
                                     Putnam Tax Exempt Money Market Fund

                                     /s/ Gordon H. Silver
                                 By: ----------------------------
                                     Gordon H. Silver
                                     Vice President


cc: Greg Pusch, Esq., Ropes & Gray