PRINCIPAL INVESTORS FUND, INC.
                   AMENDED AND RESTATED SUB-ADVISORY AGREEMENT
      PARTNERS LARGECAP GROWTH FUND II AND PARTNERS LARGECAP VALUE FUND II


AGREEMENT executed as of the 13th day of June, 2005 by and between PRINCIPAL
MANAGEMENT CORPORATION, an Iowa corporation (hereinafter called "the Manager"),
and AMERICAN CENTURY INVESTMENT MANAGEMENT, INC., a Delaware corporation
(hereinafter called "the Sub-Advisor").

                              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-Advisor to furnish it with
portfolio selection and related research and statistical services in connection
with the investment advisory services for the Partners LargeCap Growth Fund II
and the Partners LargeCap Value Fund II of the Fund (each hereinafter called
"the Series"), which the Manager has agreed to provide to the Fund, and the
Sub-Advisor desires to furnish such services; and

WHEREAS, The Manager has furnished the Sub-Advisor with copies properly
certified or authenticated of each of the following and will promptly provide
the Sub-Advisor 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;

     (c) The Fund's Articles of Incorporation and By-laws;

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

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

     1.  Appointment of Sub-Advisor

         In accordance with and subject to the Management Agreement, the Manager
         hereby appoints the Sub-Advisor to perform the services described in
         Section 2 below for investment and reinvestment of the securities and
         other assets of the 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-Advisor accepts such appointment
         and agrees to furnish the services hereinafter set forth for the
         compensation herein provided. The Sub-Advisor 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-Advisor

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

         (b)   Furnish to the Board of Directors of the Fund for approval (or
               any appropriate committee of such Board) a description of its
               LargeCap Growth and LargeCap Value investment strategies, with
               the understanding that the strategies are similar or identical to
               those used for other funds managed by the Sub-Advisor. The
               Manager shall ensure that the strategy is consistent with the
               Series' investment objective and policies prior to presenting the
               recommendation to the Board of Directors.

         (c)   Implement the approved investment strategy 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 Certificate 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 reasonably
               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 the
               Series.

         (e)   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 and as agreed by the Sub-Advisor in order to enable
               the Board to determine that the investment policies, procedures
               and approved investment program of the Series are being observed.
               It is generally expected that such reports will be made on a
               quarterly basis, in a format used with the level of detail agreed
               upon by the parties.

         (f)   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.

         (g)   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 the Series.

          (h)  Open accounts with broker-dealers and future commission merchants
               ("broker-dealers"),   select   broker-dealers   to   effect   all
               transactions  for the  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 the
               Series  may  be  aggregated  or,  if  appropriate,  crossed  with
               contemporaneous  purchase or sell orders of other  clients of the
               Sub-Advisor.  If any trades are crossed,  Sub-Advisor  may charge
               the Fund for reasonable  expenses  incurred in such  cross-trade,
               excluding  brokerage  commissions,  fees  (other  than  customary
               transfer fees) or other  remuneration paid in connection with the
               transaction.  A transaction  fee charged by a custodial bank will
               be  considered  a  customary  transfer  fee for  purposes of this
               agreement.  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-Advisor in a manner  consistent with the
               Sub-Advisor's  allocation policy and its fiduciary obligations to
               the Fund and to other  clients.  The  Sub-Advisor  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 the 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-Advisor
               shall use its best efforts to obtain  execution  of  transactions
               for the 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-Advisor may select brokers or
               dealers on the basis that they  provide  brokerage,  research  or
               other  services  or products  to the  Sub-Advisor.  To the extent
               consistent  with applicable law, the Sub-Advisor 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-Advisor 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-Advisor  and its affiliates have
               with respect to the Series as well as to accounts over which they
               exercise investment discretion. Not all such services or products
               need  be  used  by  the   Sub-Advisor  in  managing  the  Series.
               Notwithstanding the foregoing, nothing in this Agreement shall be
               construed to require the  Sub-Advisor to use any broker or dealer
               that provides brokerage,  research or other services,  nor to use
               any broker or dealer that the Manager may recommend. 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-Advisor  provided that all conditions of such
               order are complied with.

          (i)  Maintain  all  accounts,  books and records  with  respect to the
               Series as are required of an  investment  advisor of a registered
               investment  company  pursuant  to the  1940  Act  and  Investment
               Adviser's Act of 1940 (the  "Investment  Adviser's Act"), and the
               rules thereunder,  and furnish the Fund and the Manager with such
               quarterly  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-Advisor  hereby agrees that all
               records that it maintains  for the 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 Account
               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 the Series upon request by the
               Fund or the Manager.  The Sub-Advisor has no  responsibility  for
               the  maintenance  of Fund records  except  insofar as is directly
               related to the services provided to the Series.

         (j)   Observe and comply with Rule 17j-1 under the 1940 Act and the
               Sub-Advisor'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-Advisor's current Code of Ethics.
               Sub-Advisor shall promptly forward to the Manager a copy of any
               material amendment to the Sub-Advisor's Code of Ethics.

         (k)   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 the Series, all in such detail as
               the Manager or the Fund and the Sub-Advisor shall agree. The
               Sub-Advisor will make available appropriate representatives 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 the
               Series once a year.

         (l)   Provide such information as is customarily provided by a
               sub-advisor 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.

          (m)  Perform  quarterly and annual tax compliance tests to monitor the
               Series' compliance with Subchapter M of the Code. The Sub-Advisor
               shall  notify the Manager  immediately  upon having a  reasonable
               basis  for  believing  that  the  Series  has  ceased  to  be  in
               compliance  or that it might not be in  compliance in the future.
               If it is determined that the Series is not in compliance with the
               requirements  noted above, the Sub-Advisor,  in consultation with
               the  Manager,  will take  prompt  action to bring the Series back
               into  compliance  (to  the  extent   possible)  within  the  time
               permitted under the Code.

          (n)  Maintain,   in  connection  with  the  Sub-Advisor'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  strategy and restrictions
               as stated in the Fund's  prospectus  and  statement of additional
               information.

          (o)  Notify  the  Manager  of  the  filing  of any  amendments  to the
               Sub-Advisor's  Form ADV  contemporaneously  with  filing  of such
               documents with the  Securities  and Exchange  Commission or other
               regulator agency.

     3.  Prohibited Conduct

         In providing the services described in this agreement, the Sub-Advisor
         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-Advisor hereunder with respect to the Series, the Manager
         shall pay the compensation specified in Appendix A to this Agreement.

     5.  Liability of Sub-Advisor

         Neither the Sub-Advisor 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-Advisor's investment discretion in connection with selecting
         investments for the Series or as a result of the failure by the Manager
         or any of its affiliates to comply with the terms of this Agreement
         and/or any insurance, securities or other laws and rules applicable to
         the management and marketing of the Fund, except for losses resulting
         from willful misfeasance, bad faith or gross negligence of, or from
         reckless disregard of, the duties of the Sub-Advisor or any of its
         directors, officers, employees, agents, or affiliates.

         The Manager agrees that subject to the investment objective, investment
         policies and investment restrictions of the Series as set forth in the
         Fund's registration statement as in effect from time to time, the
         Sub-Advisor's adherence to a LargeCap Growth or LargeCap Value
         investment style generally used by the Sub-Advisor in managing its
         other LargeCap Growth or LargeCap Value Funds, shall not be considered
         a failure by Sub-Advisor to use its best judgment, efforts and advice
         under this Agreement.

     6.  Supplemental Arrangements

         The Sub-Advisor may enter into arrangements with other persons
         affiliated with the Sub-Advisor or with unaffiliated third parties to
         better enable the Sub-Advisor to fulfill its obligations under this
         Agreement for the provision of certain personnel and facilities to the
         Sub-Advisor, 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-Advisor 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.  Manager's Representations

         The Manager represents and warrants that (i) it is registered as an
         investment adviser under the Investment Advisers Act and will continue
         to be so registered for so long as this Agreement remains in effect;
         (ii) it is not prohibited by the 1940 Act or the Investment Advisers
         Act from performing the services contemplated by this Agreement; (iii)
         it has met, and will continue to meet for so long as this Agreement
         remains in effect, any applicable federal or state requirements, or the
         applicable requirements of any regulatory or industry self-regulatory
         agency, necessary to be met in order to perform the services
         contemplated by this Agreement; (iv) it has the authority to enter into
         and perform the services contemplated by this Agreement, and (v) it
         will immediately notify the Sub-Advisor of the occurrence of any event
         that would disqualify the Manager from serving as an investment advisor
         of an investment company pursuant to Section 9(a) of the 1940 Act or
         otherwise.

     9.  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-Advisor, 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 Fund 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-Advisor or the Fund cast in person at a meeting called
         for the purpose of voting on such approval.

         If the shareholders of the Series fail to approve the Agreement or any
         continuance of the Agreement in accordance with the requirements of the
         1940 Act, the Sub-Advisor will continue to act as Sub-Advisor with
         respect to the Series pending the required approval of the Agreement or
         its continuance or of any contract with the Sub-Advisor or a different
         manager or sub-advisor or other definitive action; provided, that the
         compensation received by the Sub-Advisor 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-Advisor,
         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 or upon
         termination of the Management Agreement, provided the Sub-Advisor has
         received prior written notice of such termination. In interpreting the
         provisions of this Section 9, the definitions contained in Section 2(a)
         of the 1940 Act (particularly the definitions of "interested person,"
         "assignment" and "voting security") shall be applied.

     10. Indemnification

          (a)  The  Sub-Advisor  agrees  to  indemnify  and  hold  harmless  the
               Manager,  any  affiliated  person  within the  meaning of Section
               2(a)(3) of the 1940 Act ("affiliated  person") of the Manager and
               each person,  if any who, within the meaning of Section 15 of the
               Securities  Act  controls  ("controlling  persons")  the Manager,
               against  any and all  losses,  claims,  damages,  liabilities  or
               litigation,  including  reasonable  legal expenses  (collectively
               "Losses")  to which  the  Manager  or such  affiliated  person or
               controlling  person of the Manager may become  subject  under the
               Securities Act, the 1940 Act, the Investment  Advisers Act, under
               any other  statute,  law,  rule or  regulation  at common  law or
               otherwise,  arising  out  of the  Sub-Advisor's  responsibilities
               hereunder  (1) to the  extent of and as a result  of the  willful
               misconduct,  bad faith, or gross  negligence by the  Sub-Advisor,
               any of the  Sub-Advisor's  employees  or  representatives  or any
               affiliate of or any person  acting on behalf of the  Sub-Advisor;
               or (2) as a result of any untrue  statement  of a  material  fact
               contained in the Registration Statement,  including any amendment
               thereof  or any  supplement  thereto,  or the  omission  to state
               therein  a  material  fact  required  to  be  stated  therein  or
               necessary to make the statement therein not misleading, if such a
               statement or omission was made in reliance upon and in conformity
               with  written  information  furnished by the  Sub-Advisor  to the
               Manager specifically for use therein; provided,  however, that in
               no case is the Sub-Advisor's indemnity in favor of the Manager or
               any affiliated person or controlling person of the Manager deemed
               to protect  such person  against any  liability to which any such
               person   would   otherwise   be  subject  by  reason  of  willful
               misconduct,  bad faith or gross  negligence in the performance of
               its  duties  or by  reason  of  its  reckless  disregard  of  its
               obligations and duties under this Agreement.

          (b)  The  Manager   agrees  to   indemnify   and  hold   harmless  the
               Sub-Advisor,  any affiliated person and any controlling person of
               the Sub-Advisor,  if any, against any and all Losses to which the
               Sub-Advisor or such  affiliated  person or controlling  person of
               the  Sub-Advisor may become subject under the Securities Act, the
               1940 Act, the  Investment  Advisers Act, under any other statute,
               law, rule or regulation, at common law or otherwise,  arising out
               of the Manager's  responsibilities  as investment  manager of the
               Fund  (1)  to  the  extent  of and  as a  result  of the  willful
               misconduct, bad faith, or gross negligence by the Manager, any of
               the Manager's employees or representatives or any affiliate of or
               any person acting on behalf of the Manager, or (2) as a result of
               any  untrue  statement  of  a  material  fact  contained  in  the
               Registration  Statement,  including any amendment  thereof or any
               supplement  thereto,  or the omission to state therein a material
               fact  required  to be stated  therein  or  necessary  to make the
               statement therein not misleading;  provided,  however, that in no
               case is the Manager's  indemnity in favor of the  Sub-Advisor  or
               any affiliated  person or controlling  person of the  Sub-Advisor
               deemed to protect such person  against any liability to which any
               such  person  would  otherwise  be  subject  by reason of willful
               misconduct,  bad faith or gross  negligence in the performance of
               its  duties  or by  reason  of  its  reckless  disregard  of  its
               obligations  and duties under this  Agreement.  It is agreed that
               the Manager's indemnification obligations under this Section will
               extend to  expenses  and costs  (including  reasonable  attorneys
               fees)  incurred by the  Sub-Advisor as a result of any litigation
               brought by the  Manager  alleging  the  Sub-Advisor's  failure to
               perform its  obligations  and duties in the manner required under
               this Agreement unless judgement is rendered for the Manager.

     11. 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-Advisor, Principal Life
         Insurance Company or the Fund cast in person at a meeting called for
         the purpose of voting on such approval.

     12. General Provisions

         (a)  Each party agrees to perform such further acts and execute such
              further documents as are necessary to effectuate the purposes
              hereof. 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, Des Moines, Iowa 50392-0200, and the
              address of the Sub-Advisor shall be 4500 Main Street, Kansas City,
              MO 64111, Attention: General Counsel.

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

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

              (2) the Sub-Advisor 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 the Series.

         (d)  The Manager shall provide (or cause the Series custodian to
              provide) timely information to the Sub-Advisor regarding such
              matters as the composition of the assets of the Series, cash
              requirements and cash available for investment in the Series, any
              applicable investment restrictions imposed by state insurance laws
              and regulations, and all other reasonable information as may be
              necessary for the Sub-Advisor to perform its duties and
              responsibilities hereunder.

         (e)  The Manager will provide Sub-Advisor promptly with any changes to
              the Fund's Articles of Incorporation, By-laws, registration
              statement, policies, procedures, instructions, and any other
              document relevant to the Sub-Advisor's management of the Series.
              The parties agree that the Sub-Advisor is not responsible for
              compliance with any such changes until notified and provided with
              a written copy of such change.

         (f)  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


                          AMERICAN CENTURY INVESTMENT MANAGEMENT, INC.


                             /s/William M. Lyons
                          By ____________________________________________
                             William M. Lyons, President






                                   APPENDIX A


     The Sub-Advisor shall serve as investment sub-advisor for the Partners
LargeCap Growth Fund II and the Partners LargeCap Value Fund II of the Fund. The
Manager will pay the Sub-Advisor, as full compensation for all services provided
under this Agreement, a fee computed at an annual rate as follows (the
"Sub-Advisor Percentage Fee"):


                           Series


         Partners LargeCap Growth Fund II

                          Sub-Advisor Fee as a
                     Percentage of Daily Net Assets


   First $50,000,000....................................  0.450%
   Next $200,000,000....................................  0.400%
   Next $500,000,000....................................  0.350%
   Above $750,000,000...................................  0.300%



                           Series


         Partners LargeCap Value Fund II

                          Sub-Advisor Fee as a
                     Percentage of Daily Net Assets


   First $200,000,000.................................... 0.400%
   Next $300,000,000..................................... 0.350%
   Next $250,000,000..................................... 0.300%
   Above $750,000,000.................................... 0.280%

     The Sub-Advisor Percentage Fee shall be accrued for each calendar day and
the sum of the daily fee accruals shall be wired monthly to the Sub-Advisor, and
shall be accompanied or supplemented by such supportive documentation as the
Sub-Advisor may reasonably request. The daily fee accruals will be computed by
multiplying the fraction of one over the number of calendar days in the year by
the applicable annual rate described above and multiplying this product by the
net assets of the Series as determined in accordance with the Series' prospectus
and statement of additional information as of the close of business on the
previous business day on which the Series was open for business.

     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.