American Century Asset Allocation Portfolios, Inc. Prospectus and Summary Prospectus Supplement LIVESTRONG® Income Portfolio ¡ LIVESTRONG® 2015 Portfolio LIVESTRONG® 2020 Portfolio ¡ LIVESTRONG® 2025 Portfolio LIVESTRONG® 2030 Portfolio ¡ LIVESTRONG® 2035 Portfolio LIVESTRONG® 2040 Portfolio ¡ LIVESTRONG® 2045 Portfolio LIVESTRONG® 2050 Portfolio ¡ LIVESTRONG® 2055 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 April 19, 2012 ■ Summary Prospectuses and Prospectuses dated December 1, 2011

Portfolio manager Irina Torelli has left American Century Investments.  All references to Ms. Torelli are hereby deleted.

©2012 American Century Proprietary Holdings, Inc. All rights reserved.

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