PRINCIPAL INVESTORS FUND, INC.
                              AMENDED AND RESTATED
                             SUB-ADVISORY AGREEMENT
            addressStreetCOLUMBUS CIRCLE INVESTORS SUB-ADVISED SERIES


AGREEMENT executed as of September 12, 2006, by and between PRINCIPAL MANAGEMENT
CORPORATION (hereinafter called "the Manager"), and COLUMBUS CIRCLE INVESTORS
("CCI") (hereinafter called "the Sub-Adviser").

                              W I T N E S S E T H:

WHEREAS, the Manager is the manager and investment adviser to each Series of
Principal Investors Fund, Inc., (the "Fund"), an open-end management investment
company registered under the Investment Company Act of 1940, as amended (the
"1940 Act"); and

WHEREAS, the Manager desires to retain the Sub-Adviser to furnish it with
investment advisory services with respect to all or a portion of the portfolio
assets of each Series of the Fund identified in Appendix A hereto (hereinafter
called "Series"), which the Manager has agreed to provide to the Fund, and the
Sub-Adviser desires to furnish such services; and

WHEREAS, The Manager has furnished the Sub-Adviser with copies properly
certified or authenticated of each of the following and will promptly provide
the Sub-Adviser with copies properly certified or authenticated of any amendment
or supplement thereto:

     (a) Management Agreement (the "Management Agreement") with the Fund;

     (b) The Fund's registration statement and financial statements as filed
         with the Securities and Exchange Commission; and

     (c) Policies, procedures or instructions adopted or approved by the Board
         of Directors of the Fund relating to obligations and services to be
         provided by the Sub-Adviser.

NOW, THEREFORE, in consideration of the premises and the terms and conditions
hereinafter set forth, the parties agree as follows:

     1.  Appointment of Sub-Adviser

         In accordance with and subject to the Management Agreement, the Manager
         hereby appoints the Sub-Adviser to perform the services described in
         Section 2 below for investment and reinvestment of the securities and
         other assets of each Series, subject to the control and direction of
         the Manager and the Fund's Board of Directors, for the period and on
         the terms hereinafter set forth. The Sub-Adviser accepts such
         appointment and agrees to furnish the services hereinafter set forth
         for the compensation herein provided. The Sub-Adviser shall for all
         purposes herein be deemed to be an independent contractor and shall,
         except as expressly provided or authorized, have no authority to act
         for or represent the Fund or the Manager in any way or otherwise be
         deemed an agent of the Fund or the Manager.

     2. Obligations of and Services to be Provided by the Sub-Adviser

         The Sub-Adviser will:

         (a)   Provide investment advisory services, including but not limited
               to research, advice and supervision for each Series.

         (b)   Furnish to the Board of Directors of the Fund for approval (or
               any appropriate committee of such Board), and revise from time to
               time as conditions require, a recommended investment program for
               each Series consistent with each Series investment objective and
               policies.

         (c)   Implement the approved investment program by placing orders for
               the purchase and sale of securities without prior consultation
               with the Manager and without regard to the length of time the
               securities have been held, the resulting rate of portfolio
               turnover or any tax considerations, subject always to the
               provisions of the Fund's registration statement, Articles of
               Incorporation and Bylaws and the requirements of the 1940 Act, as
               each of the same shall be from time to time in effect.

         (d)   Advise and assist the officers of the Fund, as requested by the
               officers, in taking such steps as are necessary or appropriate to
               carry out the decisions of its Board of Directors, and any
               appropriate committees of such Board, regarding the general
               conduct of the investment business of each Series.

         (e)   Maintain, in connection with the Sub-Adviser's investment
               advisory services obligations, compliance with the 1940 Act and
               the regulations adopted by the Securities and Exchange Commission
               thereunder and the Series' investment strategies and restrictions
               as stated in the Fund's prospectus and statement of additional
               information.

         (f)   Report to the Board of Directors of the Fund at such times and in
               such detail as the Board of Directors may reasonably deem
               appropriate in order to enable it to determine that the
               investment policies, procedures and approved investment program
               of each Series are being observed.

         (g)   Upon request, provide assistance and recommendations for the
               determination of the fair value of certain securities when
               reliable market quotations are not readily available for purposes
               of calculating net asset value in accordance with procedures and
               methods established by the Fund's Board of Directors.

         (h)   Furnish, at its own expense, (i) all necessary investment and
               management facilities, including salaries of clerical and other
               personnel required for it to execute its duties faithfully, and
               (ii) administrative facilities, including bookkeeping, clerical
               personnel and equipment necessary for the efficient conduct of
               the investment advisory affairs of each Series.

          (i)  Open  accounts  with   broker-dealers   and  futures   commission
               merchants ("broker-dealers"), select broker-dealers to effect all
               transactions  for each Series,  place all  necessary  orders with
               broker-dealers or issuers (including affiliated  broker-dealers),
               and  negotiate   commissions,   if  applicable.   To  the  extent
               consistent with applicable law,  purchase or sell orders for each
               Series may be aggregated  with  contemporaneous  purchase or sell
               orders  of  other  clients  of the  Sub-Adviser.  In  such  event
               allocation of  securities  so sold or  purchased,  as well as the
               expenses  incurred  in  the  transaction,  will  be  made  by the
               Sub-Adviser  in the manner the  Sub-Adviser  considers  to be the
               most equitable and consistent  with its fiduciary  obligations to
               the Fund and to other  clients.  The  Sub-Adviser  will report on
               such  allocations at the request of the Manager,  the Fund or the
               Fund's  Board of  Directors  providing  such  information  as the
               number of aggregated trades to which each Series was a party, the
               broker-dealers  to whom such trades were  directed  and the basis
               for the  allocation for the aggregated  trades.  The  Sub-Adviser
               shall use its best efforts to obtain  execution  of  transactions
               for each Series at prices  which are  advantageous  to the Series
               and at  commission  rates that are  reasonable in relation to the
               benefits received. However, the Sub-Adviser may select brokers or
               dealers on the basis that they  provide  brokerage,  research  or
               other  services  or products  to the  Sub-Adviser.  To the extent
               consistent  with applicable law, the Sub-Adviser may pay a broker
               or dealer an amount of  commission  for  effecting  a  securities
               transaction  in excess  of the  amount  of  commission  or dealer
               spread  another broker or dealer would have charged for effecting
               that transaction if the Sub-Adviser determines in good faith that
               such amount of  commission is reasonable in relation to the value
               of the brokerage and research  products and/or services  provided
               by such broker or dealer.  This  determination,  with  respect to
               brokerage and research products and/or services, may be viewed in
               terms  of  either  that  particular  transaction  or the  overall
               responsibilities  which the  Sub-Adviser  and its affiliates have
               with  respect to each  Series as well as to  accounts  over which
               they  exercise  investment  discretion.  Not all such services or
               products need be used by the  Sub-Adviser in managing the Series.
               In  addition,  joint  repurchase  or  other  accounts  may not be
               utilized by the Series except to the extent  permitted  under any
               exemptive  order  obtained by the  Sub-Adviser  provided that all
               conditions of such order are complied with.

          (j)  Maintain  all  accounts,  books and records  with respect to each
               Series as are required of an  investment  advisor of a registered
               investment  company  pursuant  to the  1940  Act  and  Investment
               Advisers Act of 1940 (the  "Investment  Advisers  Act"),  and the
               rules thereunder,  and furnish the Fund and the Manager with such
               periodic  and  special   reports  as  the  Fund  or  Manager  may
               reasonably  request.  In compliance with the requirements of Rule
               31a-3 under the 1940 Act, the Sub-Adviser  hereby agrees that all
               records that it maintains for each Series are the property of the
               Fund,  agrees to preserve for the periods described by Rule 31a-2
               under the 1940 Act any records that it  maintains  for the Series
               and that are  required to be  maintained  by Rule 31a-1 under the
               1940 Act, and further  agrees to  surrender  promptly to the Fund
               any records  that it  maintains  for a Series upon request by the
               Fund or the Manager.  The Sub-Adviser has no  responsibility  for
               the  maintenance  of Fund records  except  insofar as is directly
               related to the services the Sub-Adviser provides to a Series.

         (k)   Observe and comply with Rule 17j-1 under the 1940 Act and the
               Sub-Adviser's Code of Ethics adopted pursuant to that Rule as the
               same may be amended from time to time. The Manager acknowledges
               receipt of a copy of Sub-Adviser's current Code of Ethics.
               Sub-Adviser shall promptly forward to the Manager a copy of any
               material amendment to the Sub-Adviser's Code of Ethics along with
               certification that the Sub-Adviser has implemented procedures for
               administering the Sub-Adviser's Code of Ethics.

         (l)   From time to time as the Manager or the Fund may request, furnish
               the requesting party reports on portfolio transactions and
               reports on investments held by a Series, all in such detail as
               the Manager or the Fund may reasonably request. The Sub-Adviser
               will make available its officers and employees to meet with the
               Fund's Board of Directors at the Fund's principal place of
               business on due notice to review the investments of a Series.

         (m)   Provide such information as is customarily provided by a
               sub-adviser and may be required for the Fund or the Manager to
               comply with their respective obligations under applicable laws,
               including, without limitation, the Internal Revenue Code of 1986,
               as amended (the "Code"), the 1940 Act, the Investment Advisers
               Act, the Securities Act of 1933, as amended (the "Securities
               Act"), and any state securities laws, and any rule or regulation
               thereunder.


         (n)   Vote proxies received on behalf of the Series in a manner
               consistent with Sub-Adviser's proxy voting policies and
               procedures and provide a record of votes cast containing all of
               the voting information required by Form N-PX in an electronic
               format to enable the Series to file Form N-PX as required by SEC
               rule.

         (o)   Respond to tender offers, rights offerings and other voluntary
               corporate action requests affecting securities held by the Fund
               and complete and file notices of claims in connection with class
               action lawsuits concerning securities owned by the Fund.

     3.  Prohibited Conduct

         In providing the services described in this agreement, the Sub-Adviser
         will not consult with any other investment advisory firm that provides
         investment advisory services to any investment company sponsored by
         Principal Life Insurance Company regarding transactions for the Fund in
         securities or other assets.

     4.  Compensation

         As full compensation for all services rendered and obligations assumed
         by the Sub-Adviser hereunder with respect to each Series, the Manager
         shall pay the compensation specified in Appendix A to this Agreement.

     5.  Liability of Sub-Adviser

         Neither the Sub-Adviser nor any of its directors, officers, employees,
         agents or affiliates shall be liable to the Manager, the Fund or its
         shareholders for any loss suffered by the Manager or the Fund resulting
         from any error of judgment made in the good faith exercise of the
         Sub-Adviser's investment discretion in connection with selecting
         investments for a Series or as a result of the failure by the Manager
         or any of its affiliates to comply with the terms of this Agreement,
         except for losses resulting from willful misfeasance, bad faith or
         gross negligence of, or from reckless disregard of, the duties of the
         Sub-Adviser or any of its directors, officers, employees, agents, or
         affiliates.



     6.  Supplemental Arrangements

         The Sub-Adviser may enter into arrangements with other persons
         affiliated with the Sub-Adviser or with unaffiliated third parties to
         better enable the Sub-Adviser to fulfill its obligations under this
         Agreement for the provision of certain personnel and facilities to the
         Sub- Adviser, subject to written notification to and approval of the
         Manager and, where required by applicable law, the Board of Directors
         of the Fund.

     7.  Regulation

         The Sub-Adviser shall submit to all regulatory and administrative
         bodies having jurisdiction over the services provided pursuant to this
         Agreement any information, reports or other material which any such
         body may request or require pursuant to applicable laws and
         regulations.

     8.  Duration and Termination of This Agreement

         This Agreement shall become effective on the latest of (i) the date of
         its execution, (ii) the date of its approval by a majority of the Board
         of Directors of the Fund, including approval by the vote of a majority
         of the Board of Directors of the Fund who are not interested persons of
         the Manager, the Sub-Adviser, Principal Life Insurance Company or the
         Fund cast in person at a meeting called for the purpose of voting on
         such approval or (iii) if required by the 1940 Act, the date of its
         approval by a majority of the outstanding voting securities of the
         Series. It shall continue in effect thereafter from year to year
         provided that the continuance is specifically approved at least
         annually either by the Board of Directors of the Fund or by a vote of a
         majority of the outstanding voting securities of the Series and in
         either event by a vote of a majority of the Board of Directors of the
         Fund who are not interested persons of the Manager, Principal Life
         Insurance Company, the Sub-Adviser or the Fund cast in person at a
         meeting called for the purpose of voting on such approval.

         If the shareholders of a Series fail to approve the Agreement or any
         continuance of the Agreement in accordance with the requirements of the
         1940 Act, the Sub-Adviser will continue to act as Sub-Adviser with
         respect to the Series pending the required approval of the Agreement or
         its continuance or of any contract with the Sub-Adviser or a different
         manager or sub-adviser or other definitive action; provided, that the
         compensation received by the Sub-Adviser in respect to the Series
         during such period is in compliance with Rule 15a-4 under the 1940 Act.

         This Agreement may be terminated at any time without the payment of any
         penalty by the Board of Directors of the Fund or by the Sub-Adviser,
         the Manager or by vote of a majority of the outstanding voting
         securities of the Series on sixty days written notice. This Agreement
         shall automatically terminate in the event of its assignment. In
         interpreting the provisions of this Section 8, the definitions
         contained in Section 2(a) of the 1940 Act (particularly the definitions
         of "interested person," "assignment" and "voting security") shall be
         applied.

     9.  Amendment of this Agreement

         No material amendment of this Agreement shall be effective until
         approved, if required by the 1940 Act or the rules, regulations,
         interpretations or orders issued thereunder, by vote of the holders of
         a majority of the outstanding voting securities of the Series and by
         vote of a majority of the Board of Directors of the Fund who are not
         interested persons of the Manager, the Sub-Adviser, Principal Life
         Insurance Company or the Fund cast in person at a meeting called for
         the purpose of voting on such approval.

     10. General Provisions

         (a)  Each party agrees to perform such further acts and execute such
              further documents as are necessary to effectuate the purposes
              hereof. This Agreement shall be construed and enforced in
              accordance with and governed by the laws of the State of
              placeStateIowa. The captions in this Agreement are included for
              convenience only and in no way define or delimit any of the
              provisions hereof or otherwise affect their construction or
              effect.

         (b)  Any notice under this Agreement shall be in writing, addressed and
              delivered or mailed postage pre-paid to the other party at such
              address as such other party may designate for the receipt of such
              notices. Until further notice to the other party, it is agreed
              that the address of the Manager for this purpose shall be
              Principal Financial Group, CityDes Moines, StateIowa 50392-0200,
              and the address of the Sub-Adviser shall be Columbus Circle
              Investors, PlaceNameplaceMetro PlaceTypeCenter, addressStreetOne
              Station Place, addressStreetStamford CT 06902.

         (c)  The Sub-Adviser will promptly notify the Manager in writing of the
              occurrence of any of the following events:

              (1) the Sub-Adviser fails to be registered as an investment
                  adviser under the Investment Advisers Act or under the laws of
                  any jurisdiction in which the Sub-Adviser is required to be
                  registered as an investment advisor in order to perform its
                  obligations under this Agreement.

              (2) the Sub-Adviser is served or otherwise receives notice of any
                  action, suit, proceeding, inquiry or investigation, at law or
                  in equity, before or by any court, public board or body,
                  involving the affairs of a Series.

         (d)  The Manager shall provide (or cause the Series custodian to
              provide) timely information to the Sub-Adviser regarding such
              matters as the composition of the assets of a Series, cash
              requirements and cash available for investment in a Series, and
              all other reasonable information as may be necessary for the
              Sub-Adviser to perform its duties and responsibilities hereunder.

         (e) This Agreement contains the entire understanding and agreement of
the parties.

     IN WITNESS WHEREOF, the parties have duly executed this Agreement on the
date first above written.

             PRINCIPAL MANAGEMENT CORPORATION

                /s/Ernest H. Gillum
             By __________________________________________
                Ernest H. Gillum, Vice President and Chief Compliance Officer



             COLUMBUS CIRCLE INVESTORS

                 /s/Frank A. Cuttita
             By ___________________________________________
                Frank A. Cuttita, Managing Director and
                Chief Administrative Officer









                                   APPENDIX A

CCI shall serve as investment sub-adviser for each Series identified below. The
Manager will pay CCI, as full compensation for all services provided under this
Agreement, a fee, computed and paid monthly, at an annual rate as shown below of
the Series' net assets managed by CCI as of the first day of each month
allocated to CCI's management.

In calculating the fee for a series included in the table, assets of any
unregistered separate account of Principal Life Insurance Company and any
investment company sponsored by Principal Life Insurance Company to which CCI
provides investment advisory services and which have the same investment mandate
(e.g. LargeCap Growth) as the series for which the fee is calculated, will be
combined with the assets of the series to arrive at net assets.

If this Agreement becomes effective or terminates before the end of any month,
the fee (if any) for the period from the effective date to the end of such month
or from the beginning of such month to the date of termination, as the case may
be, shall be prorated according to the proportion which such period bears to the
full month in which such effectiveness or termination occurs.


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                               Compensation Table
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                         Fund Net Assets Managed by CCI

                              First          Next            Next            Next            Next            Next           Over
Fund                       $50 million    $50 million    $100 million    $200 million    $350 million    $750 million   $1.5 billion
----                       -----------    -----------    ------------    ------------    ------------    ------------   ------------


LargeCap Growth Fund          0.27%          0.25%          0.22%           0.18%           0.13%           0.09%           0.06%
------------------------- -------------- -------------- --------------- --------------- --------------- --------------- ------------

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                         Fund Net Assets Managed by CCI

                              First          Next            Next            Next            Next            Next           Over
Fund                       $25 million    $75 million    $100 million    $300 million    $500 million    $500 million   $1.5 billion
----                       -----------    -----------    ------------    ------------    ------------    ------------   ------------



MidCap Growth Fund            0.40%          0.32%          0.27%           0.23%           0.18%           0.13%           0.08%
------------------------- -------------- -------------- --------------- --------------- --------------- --------------- ------------