PRINCIPAL INVESTORS FUND, INC.
                              AMENDED AND RESTATED
                         DISTRIBUTION PLAN AND AGREEMENT
                            ADVISORS SIGNATURE CLASS


      DISTRIBUTION PLAN AND AGREEMENT made as of September 11, 2006, by and
between PRINCIPAL INVESTORS FUND, INC., a Maryland corporation (the "Fund"), and
PRINCOR FINANCIAL SERVICES CORPORATION, an Iowa corporation (the "Underwriter").

1.   This  Distribution  and  Service  Plan  (the  "Plan"),  when  effective  in
     accordance  with its  terms,  shall be the  written  plan  contemplated  by
     Securities and Exchange  Commission Rule 12b-1 under the Investment Company
     Act of 1940, as amended (the "Act") for the Advisors Signature Class shares
     of each Series identified in Appendix A, attached hereto (the "Series"),  a
     class of shares of Principal Investors Fund, Inc. (the "Fund").

2.   The Fund has entered  into a  Distribution  Agreement on behalf of the Fund
     with Princor  Financial  Services  Corporation (the  "Distributor"),  under
     which the  Distributor  uses all reasonable  efforts,  consistent  with its
     other business,  to secure  purchasers of shares of each Series of the Fund
     (the  "Shares").  Such  efforts may  include,  but neither are  required to
     include  nor  are  limited  to,  the   following:   (1)   formulation   and
     implementation  of  marketing  and  promotional  activities,  such  as mail
     promotions and television,  radio, newspaper, magazine and other mass media
     advertising; (2) preparation, printing and distribution of sales literature
     provided  to the Fund's  shareholders  and  prospective  shareholders;  (3)
     preparation,  printing and  distribution of prospectuses  and statements of
     additional  information  of the Fund and reports to  recipients  other than
     existing shareholders of the Fund; (4) obtaining such information, analyses
     and reports with respect to marketing  and  promotional  activities  as the
     Distributor  may, from time to time, deem advisable;  (5) making payment of
     sales  commission,  ongoing  commissions  and other  payments  to  brokers,
     dealers,  financial  institutions  or others who sell  Shares  pursuant  to
     Selling Agreements;  (6) paying compensation to registered  representatives
     or other employees of the Distributor who engage in or support distribution
     of the Fund's Shares; (7) paying  compensation to, and expenses  (including
     overhead  and  telephone  expenses)  of,  the  Distributor;  (8)  providing
     training,  marketing  and support to dealers and others with respect to the
     sale of Shares; (9) receiving and answering correspondence from prospective
     shareholders including distributing prospectuses,  statements of additional
     information,  and  shareholder  reports;  (10)  providing of  facilities to
     answer  questions from prospective  investors about Shares;  (11) complying
     with federal and state  securities  laws  pertaining to the sale of Shares;
     (12)  assisting  investors in  completing  application  forms and selecting
     dividend and other  account  options;  (13)  providing of other  reasonable
     assistance in connection with the  distribution of the Fund's shares;  (14)
     organizing and conducting of sales seminars and making payments in the form
     of  transactional  compensation  or promotional  incentives;  and (15) such
     other  distribution  and services  activities as the Fund determines may be
     paid for by the Fund  pursuant to the terms of this Plan and in  accordance
     with Rule 12b-1 of the Act.

3.   The  Distribution  Agreement also  authorizes the Distributor to enter into
     Service  Agreements  with  other  selling  dealers  and with banks or other
     financial institutions to provide shareholder services to existing Advisors
     Signature Class shareholders,  including without limitation,  services such
     as  furnishing  information  as to  the  status  of  shareholder  accounts,
     responding  to  telephone  and  written  inquiries  of  shareholders,   and
     assisting shareholders with tax information.

4.   In consideration for the services provided and the expenses incurred by the
     Distributor  pursuant to the Distribution  Agreement and Paragraphs 2 and 3
     hereof,  all with respect to Advisors Signature Class shares of a Series of
     the  Fund,  Advisors  Signature  Class  of  each  Series  shall  pay to the
     Distributor a fee at the annual rate of 0.35% (or such lesser amount as the
     Fund Directors may, from time to time,  determine) of the average daily net
     assets of Advisors Signature Class shares of such Series. This fee shall be
     accrued  daily and paid  monthly  or at such  other  intervals  as the Fund
     Directors shall determine.  The  determination of daily net assets shall be
     made at the close of business each day throughout the month and computed in
     the  manner  specified  in the  Fund's  then  current  Prospectus  for  the
     determination of the net asset value of the Fund's Advisors Signature Class
     shares.  The  Distributor  may use all or any  portion of the fee  received
     pursuant to this Plan to compensate securities dealers or other persons who
     have engaged in the sale of Advisors  Signature  Class shares or to pay any
     of  the  expenses   associated  with  other  activities   authorized  under
     Paragraphs 2 and 3 hereof.

5.   The Fund  presently  pays,  and will  continue to pay, a management  fee to
     Principal  Management  Corporation (the "Manager") pursuant to a Management
     Agreement between the Fund and the Manager (the "Management Agreement"). It
     is recognized that the Manager may use its management fee revenue,  as well
     as its past profits or its resources from any other source, to make payment
     to the Distributor with respect to any expenses incurred in connection with
     the  distribution  of  Advisors  Signature  Class  shares,   including  the
     activities  referred  to in  Paragraph  2 hereof.  To the  extent  that the
     payment of management  fees by the Fund to the Manager  should be deemed to
     be indirect  financing of any activity  primarily intended to result in the
     sale of Advisors  Signature  Class shares within the meaning of Rule 12b-1,
     then such payment shall be deemed to be authorized by this Plan.

6.   This Plan shall not take effect until it has been approved (a) by a vote of
     at least a majority  (as  defined in the Act) of the  outstanding  Advisors
     Signature  Class  shares of the  Series of the Fund and (b) by votes of the
     majority  of both (i) the Board of  Directors  of the Fund,  and (ii) those
     Directors of the Fund who are not  "interested  persons" (as defined in the
     Act) of the Fund and who have no direct or indirect  financial  interest in
     the  operation  of this Plan or any  agreements  related  to this Plan (the
     "Disinterested  Directors"),  cast in person at a  meeting  called  for the
     purpose of voting on this Plan or such agreements.

7.   Unless sooner terminated  pursuant to Paragraph 6, this Plan shall continue
     in effect for a period of twelve  months from the date it takes  effect and
     thereafter  shall  continue  in  effect  so  long as  such  continuance  is
     specifically approved at least annually in the manner provided for approval
     of this Plan in Paragraph 6(b).

8.   A  representative  of the  Underwriter  shall  provide to the Board and the
     Board shall  review at least  quarterly a written  report of the amounts so
     expended and the purposes for which such expenditures were made.

9.   This  Plan  may be  terminated  at any  time by vote of a  majority  of the
     Disinterested  Directors,  or by vote of a majority (as defined in the Act)
     of the  outstanding  Advisors  Signature  Class shares of the Series of the
     Fund.

10.  Any  agreement  of the Fund  related to this Plan  shall be in writing  and
     shall provide:

     A.   That such agreement may be terminated at any time,  without payment of
          any penalty,  by vote of a majority of the Disinterested  Directors or
          by a vote of a majority  (as  defined  in the Act) of the  outstanding
          Advisors  Signature Class shares of the Series of the Fund on not more
          than  sixty  (60)  days'  written  notice  to any  other  party to the
          agreement); and

     B.   That such agreement shall terminate  automatically in the event of its
          assignment.

          11.  While the Plan is in effect,  the Fund's board of directors shall
               satisfy the fund  governance  standards as defined in  Securities
               and Exchange Commission Rule 0-1(a)(7).

12.  This Plan does not  require  the  Manager or  Distributor  to  perform  any
     specific type or level of distribution  activities or to incur any specific
     level of expenses for activities  primarily  intended to result in the sale
     of Advisors Signature Class shares.

13.  The Fund shall preserve copies of this Plan and any related  agreements and
     all reports made  pursuant to  Paragraph  87, for a period of not less than
     six years from the date of the Plan, or the  agreements or such report,  as
     the case may be, the first two years in an easily accessible place.

14.  This Plan may not be  amended  to  increase  materially  the amount of Fees
     provided for in Paragraph 4 hereof unless such amendment is approved in the
     manner  provided  for initial  approval in  Paragraph 6 hereof and no other
     material amendment to this Plan shall be made unless approved in the manner
     provided for initial approval in Paragraph 6(b) hereof.

      IN WITNESS WHEREOF, the parties hereto have executed and delivered this
Plan as of the first date written above.


            PRINCIPAL INVESTORS FUND, INC.


            BY:
                 -----------------------------------------------------------
                 DAVID W. MILES, SENIOR VICE PRESIDENT AND SECRETARY


            PRINCOR FINANCIAL SERVICES CORPORATION


            BY:
                 -----------------------------------------------------------
                 MIKE J. BEER, PRESIDENT






              PRINCIPAL INVESTORS FUND, INC.
                        APPENDIX A
                          SERIES

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Bond and Mortgage Securities Fund           Partners LargeCap Value Fund
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Disciplined LargeCap Blend Fund             Partners LargeCap Value Fund I
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Diversified International Fund              Partners LargeCap Value Fund II
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Government & High Quality Bond Fund         Partners MidCap Growth Fund
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High Quality Intermediate-Term Bond Fund    Partners MidCap Growth Fund I
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Inflation Protection Fund                   Partners MidCap Growth Fund II
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International Emerging Markets Fund         Partners MidCap Value Fund
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International Growth Fund                   Partners MidCap Value Fund I
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LargeCap Growth Fund                        Partners SmallCap Blend Fund
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LargeCap S&P 500 Index Fund                 Partners SmallCap Growth Fund I
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LargeCap Value Fund                         Partners SmallCap Growth Fund II
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LifeTime 2010 Fund                          Partners SmallCap Growth Fund III
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LifeTime 2020 Fund                          Partners SmallCap Value Fund
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LifeTime 2030 Fund                          Partners SmallCap Value Fund I
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LifeTime 2040 Fund                          Partners SmallCap Value Fund II
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LifeTime 2050 Fund                          Preferred Securities Fund
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LifeTime Strategic Income Fund              Real Estate Securities Fund
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MidCap Blend Fund                           SAM Balanced Portfolio
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MidCap Growth Fund                          SAM Conservative Balanced Portfolio
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MidCap S&P 400 Index Fund                   SAM Conservative Growth Portfolio
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MidCap Value Fund                           SAM Flexible Income Portfolio
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Money Market Fund                           SAM Strategic Growth Portfolio
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Partners Global Equity Fund                 Short-Term Bond Fund
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Partners International Fund                 SmallCap Blend Fund
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Partners LargeCap Blend Fund                SmallCap Growth Fund
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Partners LargeCap Blend Fund I              SmallCap S&P 600 Index Fund
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Partners LargeCap Growth Fund               SmallCap Value Fund
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Partners LargeCap Growth Fund I             Ultra Short Bond Fund
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Partners LargeCap Growth Fund II
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