International Growth Fund (Prospectus Summary): | International Growth Fund

INTERNATIONAL GROWTH FUND    

Supplement dated June 16, 2011

to the Class A, Class B, and Class C Prospectus

for Principal Funds, Inc.

dated March 1, 2011

(as supplemented on March 14, 2011 and March 15, 2011)  

This supplement updates information currently in the Prospectus. Retain this supplement with the  

Prospectus.  

On June 14, 2011, the Board of Directors of Principal Funds, Inc. approved the acquisition of the assets  

of the International Growth Fund by the Diversified International Fund. This proposal will be submitted for  

shareholder vote at a Special Meeting of Shareholders of International Growth Fund tentatively scheduled  

for October 3, 2011. Additional information about this proposal will be provided in the Proxy  

Statement/Prospectus that is expected to be mailed to record date shareholders of International Growth  

Fund in August 2011. If shareholders approve this proposal, the acquisition is expected to occur on or  

about October 14, 2011.