American Century World Mutual Funds, Inc.

STATEMENT OF ADDITIONAL INFORMATION SUPPLEMENT

EMERGING MARKETS FUND * GLOBAL GROWTH FUND * INTERNATIONAL DISCOVERY FUND *
INTERNATIONAL GROWTH FUND * INTERNATIONAL OPPORTUNITIES FUND * INTERNATIONAL STOCK FUND
INTERNATIONAL VALUE FUND * LIFE SCIENCES FUND * NT EMERGING MARKETS FUND
NT INTERNATIONAL GROWTH FUND * TECHNOLOGY FUND

Supplement dated September 4, 2007 * Statement of Additional Information dated April 1, 2007

AS OF SEPTEMBER 4, 2007, THE ADVISOR CLASS OF GLOBAL GROWTH WAS COMBINED WITH
THE A CLASS OF THE SAME FUND. INFORMATION SPECIFIC TO THE FUND'S ADVISOR CLASS
WILL BE RESTATED WITH THE NEXT STATEMENT OF ADDITIONAL INFORMATION UPDATE TO
REFLECT CHANGES THAT RESULTED FROM THE COMBINATION. IN ADDITION, THE ADVISOR
CLASS OF EMERGING MARKETS WAS RENAMED A CLASS.

THE FOLLOWING REPLACES THE ENTRIES FOR EMERGING MARKETS AND GLOBAL GROWTH IN THE
TABLE ON PAGE 2.

FUND/CLASS                            FUND/CLASS                 INCEPTION DATE
-------------------------------------------------------------------------------
Emerging Markets
  Investor Class                        TWMIX                      09/30/1997
-------------------------------------------------------------------------------
  Institutional Class                   AMKIX                      01/28/1999
-------------------------------------------------------------------------------
  A Class                               AEMMX                      05/12/1999
-------------------------------------------------------------------------------
  C Class                               ACECX                      12/18/2001
-------------------------------------------------------------------------------
Global Growth
  Investor Class                        TWGGX                      12/01/1998
-------------------------------------------------------------------------------
  Institutional Class                   AGGIX                      08/01/2000
-------------------------------------------------------------------------------
  A Class                               AGGRX                      02/05/1999
-------------------------------------------------------------------------------
  B Class                               ACWBX                      12/01/2005
-------------------------------------------------------------------------------
  C Class                               AGLCX                      03/01/2002
-------------------------------------------------------------------------------
  R Class                               AGORX                      07/29/2005
-------------------------------------------------------------------------------





THE FOLLOWING REPLACES THE ENTRIES FOR EMERGING MARKETS, GLOBAL GROWTH,
INTERNATIONAL DISCOVERY, INTERNATIONAL GROWTH, LIFE SCIENCES AND TECHNOLOGY IN
THE TABLE ON PAGES 39 AND 40.

FUND                   CLASS                    PERCENTAGE OF STRATEGY ASSETS
--------------------------------------------------------------------------------
Emerging               Investor, A and C        1.85% of first $250 million
Markets                                         1.75% of the next $250 million
                                                1.50% of the next $500 million
                                                1.25% over $1 billion
                       ---------------------------------------------------------
                       Institutional            1.65% of first $250 million
                                                1.55% of the next $250 million
                                                1.30% of the next $500 million
                                                1.05% over $1 billion
--------------------------------------------------------------------------------
Global                 Investor, A, B,          1.30% of first $1 billion
Growth                 C and R                  1.15% of the next $1 billion
                                                1.05% over $2 billion
                       ---------------------------------------------------------
                       Institutional            1.10% of first $1 billion
                                                0.95% of the next $1 billion
                                                0.85% over $2 billion
--------------------------------------------------------------------------------
International          Investor                 1.75% of first $500 million
Discovery              and Advisor              1.40% of the next $500 million
                                                1.20% over $1 billion
                       ---------------------------------------------------------
                       Institutional            1.55% of first $500 million
                                                1.20% of the next $500 million
                                                1.00% over $1 billion
--------------------------------------------------------------------------------
International          Investor, A, B,          1.50% of first $1 billion
Growth                 C, R and Advisor         1.20% of the next $1 billion
                                                1.10% over $2 billion
                       ---------------------------------------------------------
                       Institutional            1.30% of first $1 billion
                                                1.00% of the next $1 billion
                                                0.90% over $2 billion
--------------------------------------------------------------------------------
Life Sciences          Investor, C              1.35% of first $250 million
                       and Advisor              1.25% of the next $250 million
                                                1.15% of the next $250 million
                                                1.10% over $750 million
                       ---------------------------------------------------------
                       Institutional            1.15% of first $250 million
                                                1.05% of the next $250 million
                                                0.95% of the next $250 million
                                                0.90% over $750 million
--------------------------------------------------------------------------------
Technology             Investor                 1.50% of first $250 million
                       and Advisor              1.40% of the next $250 million
                                                1.30% of the next $250 million
                                                1.20% over $750 million
                       ---------------------------------------------------------
                       Institutional            1.30% of first $250 million
                                                1.20% of the next $250 million
                                                1.10% of the next $250 million
                                                1.00% over $750 million
--------------------------------------------------------------------------------


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THE FOLLOWING REPLACES THE SECOND PARAGRAPH UNDER MULTIPLE CLASS STRUCTURE ON
PAGE 55.

The Investor Class is made available to investors directly from American Century
and/or through some financial intermediaries. Investor Class shares charge a
single unified management fee, without any load or commission payable to
American Century. Additional information regarding eligibility for Investor
Class shares may be found in the funds' prospectuses. The Institutional Class is
made available to institutional shareholders or through financial intermediaries
whose clients do not require the same level of shareholder and administrative
services from the advisor as Investor Class shareholders. As a result, the
advisor is able to charge this class a lower unified management fee. The A, B, C
and Advisor Classes also are made available through financial intermediaries,
for purchase by individual investors who receive advisory and personal services
from the intermediary. The R Class is made available through financial
intermediaries and is generally used in 401(k) and other retirement plans. The
unified management fee for the A, B, C, R and Advisor Classes is the same as for
Investor Class, but the A, B, C, R and Advisor Class shares each are subject to
a separate Master Distribution and Individual Shareholder Services Plan (the A
Class Plan, B Class Plan, C Class Plan, R Class Plan and Advisor Class Plan,
respectively, and collectively, the plans) described below. The plans have been
adopted by the funds' Board of Directors in accordance with Rule 12b-1 adopted
by the SEC under the Investment Company Act.

THE FOLLOWING REPLACES THE ADVISOR CLASS PLAN SECTION ON PAGES 62-64.

Advisor Class Plan

As described in the prospectuses, the funds' Advisor Class shares are made
available to participants in employer-sponsored retirement plans and to persons
purchasing through broker-dealers, banks, insurance companies and other
financial intermediaries that provide various administrative, shareholder and
distribution services. The funds' distributor enters into contracts with various
banks, broker-dealers, insurance companies and other financial intermediaries,
with respect to the sale of the funds' shares and/or the use of the funds'
shares in various investment products or in connection with various financial
services.

Certain recordkeeping and administrative services that are provided by the
funds' transfer agent for the Investor Class shareholders may be performed by a
plan sponsor (or its agents) or by a financial intermediary for shareholders in
the Advisor Class. In addition to such services, the financial intermediaries
provide various distribution services.

To make the funds' shares available through such plans and financial
intermediaries, and to compensate them for these services, the funds' Board of
Directors has adopted the Advisor Class Plan. Prior to September 4, 2007, the
Advisor Class Plan required the Advisor Class to pay 0.50% annually of the
aggregate average daily net assets of the funds' Advisor Class shares, 0.25% for
certain ongoing shareholder and administrative services (as described below) and
0.25% for distribution services, including past distribution services (as
described below). However, at a shareholder meeting on July 27, 2007, the
Advisor Class shareholders approved a decrease in the fee required by the
Advisor Class Plan of 0.25%, and a corresponding increase in the Advisor Class
management fee. This change was made because the administrative services portion
of the 12b-1 fee does not need to be made out of the 12b-1 plan, but may
properly be made out of the funds' unified fee, consistent with the other
classes of the funds. This change resulted in no difference in the overall fee
for the Advisor Class, but will lower the amount of the 12b-1 fee charged under
the Advisor Class Plan from and after September 4, 2007. After that date,
pursuant to the Advisor Class Plan, the Advisor Class pays the funds'
distributor 0.25% annually of the aggregate average daily net assets of the
funds' Advisor Class shares, which is paid for certain ongoing individual
shareholder services (as described below) and for distribution services,
including past distribution services (as described below). This payment is fixed
at 0.25% and is not based on expenses incurred by the distributor. During the
fiscal year ended November 30, 2006, the aggregate amount of fees paid under the
Advisor Class Plan was:

      Emerging Markets                       $24,798
      Global Growth                          $25,614
      International Discovery                   $128
      International Growth                $1,525,127
      Life Sciences                             $726
      Technology                                $608


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The distributor then makes these payments to the financial intermediaries
(including underwriters and broker-dealers, who may use some of the proceeds to
compensate sales personnel) who offer the Advisor Class shares in payment for
provision of the services described below. No portion of these payments is used
by the distributor to pay for advertising, printing costs or interest expenses.

Prior to September 4, 2007, 0.25% of the fee charged pursuant to the Advisor
Class Plan was for a variety of shareholder services, including, but not limited
to:

(a)  receiving, aggregating and processing purchase, exchange and
     redemption requests from beneficial owners (including contract owners of
     insurance products that use the funds as underlying investment media) of
     shares and placing purchase, exchange and redemption orders with the funds'
     distributor;

(b)  providing shareholders with a service that invests the assets of their
     accounts in shares according to specific or preauthorized instructions;

(c)  processing dividend payments from a fund on behalf of shareholders and
     assisting shareholders in changing dividend options, account designations
     and addresses;

(d)  providing and maintaining elective services such as check writing and
     wire transfer services;

(e)  acting as shareholder of record and nominee for beneficial owners;

(f)  maintaining account records for shareholders and/or other beneficial
     owners;

(g)  issuing confirmations of transactions;

(h)  providing subaccounting for shares beneficially owned by customers of
     third parties or providing the information to a fund as necessary for such
     subaccounting;

(i)  preparing and forwarding shareholder communications from the funds
     (such as proxies, shareholder reports, annual and semiannual financial
     statements, and dividend, distribution and tax notices) to shareholders
     and/or other beneficial owners; and

(j)  providing other similar administrative and sub-transfer agency
     services.

Shareholder services do not include those activities and expenses that are
primarily intended to result in the sale of additional shares of the funds.
During the fiscal year ended November 30, 2006, the amount of fees paid under
the Advisor Class Plan for shareholder services was:

      Emerging Markets                     $12,399
      Global Growth                        $12,807
      International Discovery                  $64
      International Growth                $762,583
      Life Sciences                           $363
      Technology                              $304

Although these services are still being provided by the financial
intermediaries, after September 4, 2007, they will be reimbursed by the funds'
advisor out of the unified management fee rather than out of a 12b-1 fee, as
described above.

Distribution services include any activity undertaken or expense incurred that
is primarily intended to result in the sale of Advisor Class shares, which
services may include but are not limited to:

(a)  the payment of sales commissions, ongoing commissions and other
     payments to brokers, dealers, financial institutions or others who sell
     Advisor Class shares pursuant to selling agreements;

(b)  compensation to registered representatives or other employees of the
     distributor who engage in or support distribution of the funds' Advisor
     Class shares;

(c)  compensation to, and expenses (including overhead and telephone
     expenses) of the distributor;

(d)  printing prospectuses, statements of additional information and
     reports for other-than-existing investors;

(e)  preparing, printing and distributing sales literature and advertising
     materials provided to the funds' investors and prospective investors;

(f)  receiving and answering correspondence from prospective investors,
     including distributing prospectuses, statements of additional information
     and shareholder reports;

(g)  providing facilities to answer questions from prospective investors
     about fund shares;

(h)  complying with federal and state securities laws pertaining to the
     sale of fund shares;


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(i)  assisting investors in completing application forms and selecting
     dividend and other account options;

(j)  providing other reasonable assistance in connection with the
     distribution of fund shares;

(k)  organizing and conducting sales seminars and payments in the form of
     transactional compensation or promotional incentives;

(l)  profit on the foregoing;

(m)  the payment of "service fees" for the provision of personal,
     continuing services to investors, as contemplated by the Conduct Rules of
     the FINRA; and

(n)  such other distribution and services activities as the advisor
     determines may be paid for by the funds pursuant to the terms of this
     Agreement and in accordance with Rule 12b-1 of the Investment Company Act.

During the fiscal year ended November 30, 2006, the amount of fees paid under
the Advisor Class Plan for distribution services was:

      Emerging Markets                   $12,399
      Global Growth                      $12,807
      International Discovery                $64
      International Growth              $762,544
      Life Sciences                         $363
      Technology                            $304

Beginning on September 4, 2007, a portion of the 12b-1 fee will be paid to the
distributor for certain individual shareholder services. These payments may be
made for a variety of individual shareholder services, including, but not
limited to:

(a)  providing individualized and customized investment advisory services,
     including the consideration of shareholder profiles and specific goals;

(b)  creating investment models and asset allocation models for use by
     shareholders in selecting appropriate funds;

(c)  conducting proprietary research about investment choices and the
     market in general;

(d)  periodic rebalancing of shareholder accounts to ensure compliance with
     the selected asset allocation;

(e)  consolidating shareholder accounts in one place; and

(f)  other individual services.


Individual shareholder services do not include those activities and expenses
that are primarily intended to result in the sale of additional shares of the
funds.

As of September 4, 2007, the Advisor Classes of Emerging Markets and Global
Growth were renamed A Class and became subject to the A Class Plan.


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American Century Investment Services, Inc., Distributor

©2006 American Century Proprietary Holdings, Inc. All rights reserved.

The American Century Investments logo, American Century and American Century
Investments are service marks of American Century Proprietary Holdings, Inc.

SH-SPL-56570 0709