0000898745 2012-12-14 2012-12-14 0000898745 ck0000898745:S000014241Member ck0000898745:C000092703Member 2012-12-14 2012-12-14 0000898745 ck0000898745:S000014241Member ck0000898745:C000038750Member 2012-12-14 2012-12-14 0000898745 ck0000898745:S000014241Member ck0000898745:C000038749Member 2012-12-14 2012-12-14 0000898745 ck0000898745:S000014241Member ck0000898745:C000038748Member 2012-12-14 2012-12-14 0000898745 ck0000898745:P0001-S000014241Member ck0000898745:S000014241Member 2012-12-14 2012-12-14 Other 2012-12-14 PRINCIPAL FUNDS INC 0000898745 false 2012-12-14 2012-12-14 2012-02-29 High Yield Fund    <p class="MsoNormal" style="margin-top:0in;margin-right:0in;margin-left:0in;font-size:11.0pt;font-family:'calibri','sans-serif';margin-bottom:0in;margin-bottom:.0001pt;line-height: normal;text-autospace:none">  <p class="MsoNormal" align="center" style="font-size:11.0pt;font-family:'calibri','sans-serif';margin-top:.05pt;margin-right:0in; margin-bottom:0in;margin-left:0in;margin-bottom:.0001pt;text-align:center; line-height:normal;text-autospace:none">Supplement dated December 14, 2012 <p class="MsoNormal" align="center" style="font-size:11.0pt;font-family:'calibri','sans-serif';margin-top:.05pt;margin-right:0in; margin-bottom:0in;margin-left:0in;margin-bottom:.0001pt;text-align:center; line-height:normal;text-autospace:none">to the Class A, Class B, Class C, and Class P Shares Prospectus <p class="MsoNormal" align="center" style="font-size:11.0pt;font-family:'calibri','sans-serif';margin-top:.05pt;margin-right:0in; margin-bottom:0in;margin-left:0in;margin-bottom:.0001pt;text-align:center; line-height:normal;text-autospace:none">for Principal Funds, Inc. <p class="MsoNormal" align="center" style="font-size:11.0pt;font-family:'calibri','sans-serif';margin-top:.05pt;margin-right:0in; margin-bottom:0in;margin-left:0in;margin-bottom:.0001pt;text-align:center; line-height:normal;text-autospace:none">dated February 29, 2012 <p class="MsoNormal" align="center" style="font-size:11.0pt;font-family:'calibri','sans-serif';margin-top:.05pt;margin-right:0in; margin-bottom:0in;margin-left:0in;margin-bottom:.0001pt;text-align:center; line-height:normal;text-autospace:none">  <p class="MsoNormal" align="center" style="font-size:11.0pt;font-family:'calibri','sans-serif';margin-top:.05pt;margin-right:0in; margin-bottom:0in;margin-left:0in;margin-bottom:.0001pt;text-align:center; line-height:normal;text-autospace:none">(as supplemented on March 16, 2012, March 29, 2012, April 9, 2012, April 20, 2012, May 11, 2012, June 15, 2012, July 17, 2012, July 27, 2012, September 14, 2012, November 13, 2012, and November 27, 2012) <p class="MsoNormal" style="font-size:11.0pt;font-family:'calibri','sans-serif';margin-top:.05pt;margin-right:0in;margin-bottom:0in; margin-left:0in;margin-bottom:.0001pt;line-height:normal;text-autospace:none">  <p class="MsoNormal" style="font-size:11.0pt;font-family:'calibri','sans-serif';margin-top:.05pt;margin-right:0in;margin-bottom:0in; margin-left:0in;margin-bottom:.0001pt;line-height:normal;text-autospace:none">This supplement updates information currently in the Prospectus. Retain this supplement with the Prospectus. <p class="MsoNormal" style="font-size:11.0pt;font-family:'calibri','sans-serif';margin-top:.05pt;margin-right:0in;margin-bottom:0in; margin-left:0in;margin-bottom:.0001pt;line-height:normal;text-autospace:none">  <p class="MsoNormal" style="font-size:11.0pt;font-family:'calibri','sans-serif';margin-top:.05pt;margin-right:0in;margin-bottom:0in; margin-left:0in;margin-bottom:.0001pt;line-height:normal;page-break-after:avoid; text-autospace:none">FUND SUMMARIES   Principal Investment Strategies <p class="MsoNormal" style="font-size:11.0pt;font-family:'calibri','sans-serif';margin-top:9.0pt;margin-right:0in;margin-bottom:0in; margin-left:0in;margin-bottom:.0001pt;line-height:normal;text-autospace:none">Effective March 1, 2013, delete the first sentence under the Principal Investment Strategies and substitute: <p class="MsoNormal" style="font-size:11.0pt;font-family:'calibri','sans-serif';margin-top:.05pt;margin-right:0in;margin-bottom:0in; margin-left:0in;margin-bottom:.0001pt;line-height:normal;text-autospace:none">Under normal circumstances, the Fund invests at least 80% of its net assets, plus any borrowings for investment purposes, in below investment grade bonds (sometimes called “high yield bonds” or "junk bonds") which are rated at the time of purchase Ba1 or lower by Moody's and BB+ or lower by S&P (if the bond has been rated by only one of those agencies, that rating will determine whether the bond is below investment grade; if the bond has not been rated by either of those agencies the Sub-Advisor will determine whether the bond is of a quality comparable to those rated below investment grade).   CPHYX CBHYX CCHIX PYHPX