American Century Asset Allocation Portfolios, Inc.

STATEMENT OF ADDITIONAL INFORMATION SUPPLEMENT

MY RETIREMENT 2015 PORTFOLIO
MY RETIREMENT 2025 PORTFOLIO
MY RETIREMENT 2035 PORTFOLIO
MY RETIREMENT 2045 PORTFOLIO
MY RETIREMENT INCOME PORTFOLIO
ONE CHOICE PORTFOLIO®: VERY CONSERVATIVE
ONE CHOICE PORTFOLIO®: CONSERVATIVE
ONE CHOICE PORTFOLIO®: MODERATE
ONE CHOICE PORTFOLIO®: AGGRESSIVE
ONE CHOICE PORTFOLIO®: VERY AGGRESSIVE

Supplement  dated January 13, 2006 * Statement of Additional  Information  dated
December 1, 2005

THE FOLLOWING PARAGRAPH IS INSERTED AS THE FOURTH PARAGRAPH, ABOVE THE SECTION
TITLED Portfolio Managers, ON PAGE 42:

Certain investments may be appropriate for the funds and also for other clients
advised by the advisor. Investment decisions for the funds and other clients are
made with a view to achieving their respective investment objectives after
consideration of such factors as their current holdings, availability of cash
for investment and the size of their investment generally. A particular security
may be bought or sold for only one client or fund, or in different amounts and
at different times for more than one but less than all clients or funds. A
particular security may be bought for one client or fund on the same day it is
sold for another client or fund, and a client or fund may hold a short position
in a particular security at the same time another client or fund holds a long
position. In addition, purchases or sales of the same security may be made for
two or more clients or funds on the same date. The advisor has adopted
procedures designed to ensure such transactions will be allocated among clients
and funds in a manner believed by the advisor to be equitable to each. In some
cases this procedure could have an adverse effect on the price or amount of the
securities purchased or sold by a fund.

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.

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