AMERICAN CENTURY CALIFORNIA TAX-FREE AND MUNICIPAL FUNDS
                        AMERICAN CENTURY MUNICIPAL TRUST

             SUPPLEMENT TO THE STATEMENTS OF ADDITIONAL INFORMATION

                      SUPPLEMENT DATED FEBRUARY 2, 1998 TO

            American Century California Tax-Free And Municipal Funds
          Statement of Additional Information dated December 15, 1997,
                                     and to
                        American Century Municipal Trust
           Statement of Additional Information dated September 2, 1997


ON  PAGE 6 IN THE  STATEMENT  OF  ADDITIONAL  INFORMATION  OF  AMERICAN  CENTURY
CALIFORNIA  TAX-FREE AND MUNICIPAL FUNDS, THE SECOND PARAGRAPH UNDER THE HEADING
"SHORT-TERM SECURITIES (VARIABLE-PRICE FUNDS)" IS DELETED.

ON  PAGE 6 IN THE  STATEMENT  OF  ADDITIONAL  INFORMATION  OF  AMERICAN  CENTURY
CALIFORNIA  TAX-FREE AND MUNICIPAL FUNDS,  PLEASE INSERT THE FOLLOWING PARAGRAPH
ABOVE THE  SECTION  TITLED  "CONCENTRATION  OF ASSETS IN  OBLIGATIONS  ISSUED TO
FINANCE SIMILAR PROJECTS OR FACILITIES".

OTHER INVESTMENT COMPANIES

   Each of the funds may invest up to 5% of its total assets in any money market
fund,  including  those advised by the manager,  provided that the investment is
consistent  with the fund's  investment  policies  and  restrictions.  Under the
Investment  Company  Act of 1940 (the  "Investment  Company  Act"),  the  fund's
investment  in such  securities,  subject to certain  exceptions,  currently  is
limited to (a) 3% of the total voting stock of any one investment  company,  (b)
5% of the fund's total assets with respect to any one investment company and (c)
10% of the fund's total assets in the aggregate.  Such purchases will be made in
the open market  where no  commission  or profit to a sponsor or dealer  results
from  the  purchase  other  than  the  customary  brokers'  commissions.   As  a
shareholder of another  investment  company, a fund would bear, along with other
shareholders,  its pro rata portion of the other investment  company's expenses,
including  advisory fees.  These expenses would be in addition to the management
fee that each fund bears directly in connection with its own operations.

ON  PAGE 8 IN THE  STATEMENT  OF  ADDITIONAL  INFORMATION  OF  AMERICAN  CENTURY
MUNICIPAL  TRUST,  PLEASE  DELETE THE FIRST  SENTENCE  UNDER THE HEADING  "OTHER
INVESTMENT COMPANIES" AND REPLACE WITH THE FOLLOWING.

   Each of the funds may invest up to 5% of its total assets in any money market
fund,  including  those advised by the manager,  provided that the investment is
consistent with the fund's investment policies and restrictions.

ON PAGE 16 IN THE  STATEMENT  OF  ADDITIONAL  INFORMATION  OF  AMERICAN  CENTURY
CALIFORNIA  TAX-FREE  AND  MUNICIPAL  FUNDS AND ON PAGE 14 IN THE  STATEMENT  OF
ADDITIONAL  INFORMATION OF AMERICAN CENTURY  MUNICIPAL TRUST,  PLEASE INSERT THE
FOLLOWING PARAGRAPH ABOVE THE SECTION TITLED "TAXES".

MULTIPLE CLASS PERFORMANCE ADVERTISING

   Pursuant to the Multiple Class Plan, the funds may issue  additional  classes
of existing  funds or introduce  new funds with multiple  classes  available for
purchase.  To the extent a new class is added to an existing  fund,  the manager
may, in compliance with SEC and NASD rules,  regulations and guidelines,  market
the new class of shares  using the  historical  performance  information  of the
original class of shares. When quoting performance information for the new class
of shares for  periods  prior to the first full  quarter  after  inception,  the
original class'  performance will be restated to reflect the expenses of the new
class.  For  periods  after the  first  full  quarter  after  inception,  actual
performance of the new class will be used.

ON PAGE 20 IN THE  STATEMENT  OF  ADDITIONAL  INFORMATION  OF  AMERICAN  CENTURY
CALIFORNIA  TAX-FREE  AND  MUNICIPAL  FUNDS AND ON PAGE 19 IN THE  STATEMENT  OF
ADDITIONAL  INFORMATION OF AMERICAN CENTURY  MUNICIPAL TRUST,  PLEASE DELETE THE
REFERENCES  TO JAMES M.  BENHAM AND JAMES E.  STOWERS  III UNDER THE  HEADING OF
"TRUSTEES AND OFFICERS-TRUSTEES" AND INSERT THE FOLLOWING:

   *WILLIAM M. LYONS,  Trustee (1998).  Mr. Lyons is President,  Chief Operating
Officer and General Counsel of ACC; Executive Vice President and General Counsel
of ASC and ACIS; Assistant Secretary of ACC; and Secretary of ACS and ACIS.

   *JAMES E. STOWERS III,  Chairman of the Board of Trustees  (1998) and Trustee
(1995).  Mr. Stowers III is Chief  Executive  Officer and Director of ACC; Chief
Executive Officer and Director of ACS and ACIS.

ON PAGE 21 IN THE  STATEMENT  OF  ADDITIONAL  INFORMATION  OF  AMERICAN  CENTURY
CALIFORNIA  TAX-FREE  AND  MUNICIPAL  FUNDS AND ON PAGE 19 IN THE  STATEMENT  OF
ADDITIONAL  INFORMATION OF AMERICAN CENTURY  MUNICIPAL TRUST,  PLEASE DELETE THE
PARAGRAPHS  UNDER THE HEADING OF "TRUSTEES  AND  OFFICERS-OFFICERS"  AND REPLACE
WITH THE FOLLOWING:

   RICHARD W. INGRAM, President (1998); Executive Vice President and Director of
Client Services and Treasury Administration,  Funds Distributor, Inc. (FDI). Mr.
Ingram  joined FDI in 1995.  Prior to joining  FDI,  Mr.  Ingram  served as Vice
President and Division Manager of First Data Investor Services Group, Inc. (from
March  1994 to  November  1995) and  before  that as Vice  President,  Assistant
Treasurer and Tax Director-Mutual  Funds of The Boston Company,  Inc. (from 1989
to 1994).

   *DOUGLAS  A. PAUL,  Secretary  (1988),  Vice  President  (1990),  and General
Counsel (1990); Vice President and Associate General Counsel, ACS.

   *MARYANNE  ROEPKE,  CPA,  Treasurer  (1995) and Vice President  (1998);  Vice
President and Assistant Treasurer of ACS.

   CHRISTOPHER J. KELLEY,  Vice President  (1998);  Vice President and Associate
General Counsel of FDI. Mr. Kelley joined FDI in 1996. Prior to joining FDI, Mr.
Kelley served as Assistant  Counsel at Forum Financial Group (from April 1994 to
July 1996) and before that as a compliance  officer for Putnam Investments (from
1992 to 1994).

   MARY A. NELSON, Vice President (1998); Vice President and Manager of Treasury
Services and  Administration  of FDI. Ms.  Nelson  joined FDI in 1995.  Prior to
joining FDI, Ms. Nelson served as Assistant  Vice  President and Client  Manager
for The Boston Company, Inc. (from 1989 to 1994).

   *JON ZINDEL,  Tax Officer (1997);  Director of Taxation (1996);  Tax Manager,
Price Waterhouse LLP (1989).

   *C. JEAN WADE, Controller, (1996).

ON PAGE 25 IN THE  STATEMENT  OF  ADDITIONAL  INFORMATION  OF  AMERICAN  CENTURY
CALIFORNIA  TAX-FREE  AND  MUNICIPAL  FUNDS AND ON PAGE 23 IN THE  STATEMENT  OF
ADDITIONAL  INFORMATION OF AMERICAN CENTURY  MUNICIPAL TRUST,  PLEASE DELETE THE
FIRST SENTENCE UNDER THE HEADING  "DISTRIBUTION OF FUND SHARES" AND REPLACE WITH
THE FOLLOWING:

   The Funds' shares are distributed by FDI, a registered broker-dealer.


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                                                                  American
                                                               Century(reg.sm)


                                                                 P.O. Box 419200
                                                          Kansas City, Missouri
                                                                     64141-6200
                                                 1-800-345-2021 or 816-531-5575

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