As filed with the Securities and Exchange Commission on May 18, 2007

                                                     Registration No. 333-____
     =====================================================================

                                  UNITED STATES
                       SECURITIES AND EXCHANGE COMMISSION
                             WASHINGTON, D.C. 20549

                                 ---------------

                                    FORM S-8

                             REGISTRATION STATEMENT
                                      UNDER
                           THE SECURITIES ACT OF 1933

                                ----------------

                         PRINCIPAL FINANCIAL GROUP, INC.
             (Exact name of registrant as specified in its charter)

        DELAWARE                                              42-1520346
(State or other jurisdiction of                             (I.R.S. Employer
 incorporation or organization)                            Identification No.)

                                 711 HIGH STREET
                             DES MOINES, IOWA 50392
                    (Address of Principal Executive Offices)


            PRINCIPAL FINANCIAL GROUP, INC. 2005 STOCK INCENTIVE PLAN
            PRINCIPAL FINANCIAL GROUP, INC. 2005 DIRECTORS STOCK PLAN
                            (Full title of the Plans)


                              KAREN E. SHAFF, ESQ.
                  EXECUTIVE VICE PRESIDENT AND GENERAL COUNSEL
                         PRINCIPAL FINANCIAL GROUP, INC.
                                 711 HIGH STREET
                             DES MOINES, IOWA 50392
                                 (515) 247-5111
            (Name, address and telephone number of agent for service)

     =====================================================================

                                       1
<PAGE>

<TABLE>
<CAPTION>




                         CALCULATION OF REGISTRATION FEE

-------------------------------------------------------------------------------------------------------------
<S>                            <C>                <C>                 <C>               <C>
                                                   Proposed            Proposed
Title                                              maximum             maximum
Securities to be                Amount to be       offering price per  aggregate          Amount of
registered                      registered         share(2)            offering price(2)  registration fee
-------------------------------------------------------------------------------------------------------------
Common Stock,
par value $.01
per share                       24,500,000(1)       $60.60             $1,484,700,000.00  $45,580.29
-------------------------------------------------------------------------------------------------------------
</TABLE>


(1)      Consists  of shares  of  common  stock to be  offered  pursuant  to the
         Principal  Financial  Group,  Inc.  2005 Stock  Incentive  Plan and the
         Principal  Financial  Group,  Inc.  2005  Directors  Stock  Plan.  Such
         indeterminate  number of additional  shares as may be issuable pursuant
         to the  recapitalization  provisions  under the employee  benefit plans
         described herein is hereby also registered.

(2)      Estimated  solely for the purposes of determining the  registration fee
         pursuant  to the  provisions  of Rules  457(c)  and  457(h)  under  the
         Securities  Act  based on the  average  of high and low  prices  of the
         Common Stock as reported on the New York Stock Exchange  Composite Tape
         on May 16, 2007, which was $60.60.


                                       2
<PAGE>


                                     PART II

               INFORMATION REQUIRED IN THE REGISTRATION STATEMENT

ITEM 3.  INCORPORATION OF DOCUMENTS BY REFERENCE

The following documents are incorporated by reference:

     (a)  Principal  Financial Group,  Inc.'s Annual Report on Form 10-K for the
          year ended December 31, 2006 (filed February 28, 2007)

     (b)  Principal  Financial  Group,  Inc.'s Quarterly Report on Form 10-Q for
          the quarter ended March 31, 2007 (filed May 2, 2007)

     (c)   Principal  Financial  Group's  Current  Reports  on Form  8-K  dated:
           December  31,  2006 (filed  January 3, 2007)  January 18, 2007 (filed
           January 18, 2007) February 5, 2007 (filed February 6, 2007) April 23,
           2007 (filed April 23, 2007) April 30, 2007 (filed May 1, 2007)

     (d) Amendment  No. 4 to  Principal  Financial  Group,  Inc.'s  Registration
         Statement on Form S- 1, file number 333-62558,  and related Prospectus,
         as filed with the  Securities  and Exchange  Commission  on October 22,
         2001.  Information relating to Principal Financial Group, Inc.'s common
         stock is set forth under the caption  "Description of Capital Stock and
         Change of Control Related Provisions" in the Registration  Statement on
         Form S-1.

In addition, all documents subsequently filed by Principal Financial Group, Inc.
pursuant to Sections 13(a),  13(c), 14 and 15(d) of the Securities  Exchange Act
of 1934, prior to the filing of a post-effective  amendment which indicates that
all securities offered hereby have been sold or which deregisters all securities
then remaining  unsold,  shall be deemed to be incorporated by reference in this
Registration  Statement  and to be a part  hereof  from the date of filing  such
documents.

Any statement contained in a document  incorporated or deemed to be incorporated
by reference herein shall be deemed to be modified or superseded for purposes of
this Registration  Statement to the extent that a statement contained herein (or
in any other subsequently filed document which also is incorporated or deemed to
be incorporated by reference herein) modifies or supersedes such statement.  Any
such  statement  so modified  or  superseded  shall not be deemed,  except as so
modified or superseded, to constitute a part of this Registration Statement.

ITEM 4.  DESCRIPTION OF SECURITIES

Not applicable.

                                       3
<PAGE>


ITEM 5.  INTERESTS OF NAMED EXPERTS AND COUNSEL

The validity of the securities being offered under this  Registration  Statement
are  being  passed  upon  for the  Registrant  by  Karen  E.  Shaff,  Esq.,  the
Registrant's Executive Vice President and General Counsel. Ms. Shaff is eligible
to receive shares under the Principal Financial Group, Inc. 2005 Stock Incentive
Plan, whose shares are subject to this Registration Statement.


ITEM 6.  INDEMNIFICATION OF DIRECTORS AND OFFICERS

Our  directors  and  officers may be  indemnified  against  liabilities,  fines,
penalties  and claims  imposed upon or asserted  against them as provided in the
Delaware  General  Corporation  Law and our  certificate  of  incorporation  and
by-laws.  Such  indemnification  covers  all costs and  expenses  incurred  by a
director or officer in his or her capacity as such. The board of directors, by a
majority  vote  of  a  quorum  of  disinterested  directors  or,  under  certain
circumstances,  independent  counsel  appointed by the board of directors,  must
determine that the director or officer seeking indemnification was not guilty of
willful  misconduct  or a knowing  violation of criminal  law. In addition,  the
Delaware General Corporation Law and our certificate of incorporation may, under
certain  circumstances,  eliminate  the liability of directors and officers in a
stockholder or derivative proceeding.

If the person  involved  is not a director  or  officer of  Principal  Financial
Group, Inc., the board of directors may cause Principal Financial Group, Inc. to
indemnify,  to the same extent  allowed for our  directors  and  officers,  such
person  who was or is a party to a  proceeding  by reason of the fact that he or
she is or was our  employee  or agent,  or is or was serving at our request as a
director, officer, employee or agent of another corporation,  partnership, joint
venture, trust, employee benefit plan or other enterprise.

We have  policies  in force and  effect to insure  our  directors  and  officers
against such losses which they or any of them will become  legally  obligated to
pay by reason of any  actual or  alleged  error or  misstatement  or  misleading
statement or act or omission or neglect or breach of duty by such  directors and
officers in the discharge of their duties, individually or collectively, or as a
result of any  matter  claimed  against  them  solely  by reason of their  being
directors  or  officers.  Such  coverage  is limited by the  specific  terms and
provisions of the insurance policies.

ITEM 7.  EXEMPTION FROM REGISTRATION CLAIMED

Not applicable.

ITEM 8.  EXHIBITS



                                       4
<PAGE>

An Exhibit Index, containing a list of all exhibits filed with this Registration
Statement, is included on page nine.


ITEM 9.  UNDERTAKINGS

          (a)  Rule 415 Offering. The undersigned Registrant hereby undertakes:

          (1)  To file,  during  any  period in which  offers or sales are being
               made, a post-effective amendment to this Registration Statement:

               (i)  To include any  Prospectus  required by section  10(a)(3) of
                    the  Securities  Act of  1933,  unless  the  information  is
                    contained  in  periodic  reports  filed  by  the  Registrant
                    pursuant to section 13 or section  15(d) of the Exchange Act
                    of  1934  that  are   incorporated   by   reference  in  the
                    Registration Statement;

               (ii) To reflect  in the  Prospectus  any facts or events  arising
                    after the effective date of the  Registration  Statement (or
                    the most recent  post-effective  amendment  thereof)  which,
                    individually  or in the  aggregate,  represent a fundamental
                    change  in the  information  set  forth in the  Registration
                    Statement,  unless the  information is contained in periodic
                    reports  filed by the  Registrant  pursuant to section 13 or
                    15(d) of the Exchange Act of 1934 that are  incorporated  by
                    reference in the Registration Statement;

               (iii) To include any  material  information  with  respect to the
                    plan  of  distribution  not  previously   disclosed  in  the
                    Registration  Statement  or  any  material  change  to  such
                    information in the Registration Statement.

          (2)  That,  for the purpose of  determining  any  liability  under the
               Securities  Act,  each  such  post-effective  amendment  shall be
               deemed  to  be a  new  registration  statement  relating  to  the
               securities  offered therein,  and the offering of such securities
               at that time shall be deemed to be the initial bona fide offering
               thereof.

          (3)  To  remove  from   registration  by  means  of  a  post-effective
               amendment any of the  securities  being  registered  which remain
               unsold at the termination of the offering.

          (b)  Subsequent  Exchange Act Documents.  The  undersigned  Registrant
               hereby undertakes that, for purposes of determining any liability
               under the Securities Act, each filing of the Registrant's  annual
               report pursuant to section 13(a) or section 15(d) of the Exchange
               Act (and,  where  applicable,  each filing of an employee benefit
               plan's  annual  report  pursuant to section 15(d) of the Exchange
               Act)  that  is  incorporated  by  reference  in the  Registration
               Statement  shall be  deemed  to be a new  registration  statement
               relating to the securities  offered therein,  and the offering of
               such  securities  at that time shall be deemed to be the  initial
               bona fide offering thereof.

          (c)  Indemnification.   Insofar  as  indemnification  for  liabilities
               arising under the  Securities  Act may be permitted to directors,
               officers and  controlling  persons of the Registrant  pursuant to


                                       5
<PAGE>

               the foregoing provisions,  or otherwise,  the Registrant has been
               advised  that  in the  opinion  of the  Securities  and  Exchange
               Commission  such  indemnification  is  against  public  policy as
               expressed in the Securities Act and is, therefore, unenforceable.
               In the  event  that a  claim  for  Indemnification  against  such
               liabilities (other than the payment by the Registrant of expenses
               incurred or paid by a director,  officer or controlling person of
               the Registrant in the successful  defense of any action,  suit or
               proceeding) is asserted by such director,  officer or controlling
               person in connection with the securities  being  registered,  the
               Registrant will,  unless in the opinion of its counsel the matter
               has been settled by controlling  precedent,  submit to a court of
               appropriate    jurisdiction    the    question    whether    such
               indemnification  by it is against  public  policy as expressed in
               the Securities Act and will be governed by the final adjudication
               of such issue.


                                       6
<PAGE>


                                   SIGNATURES

The Registrant.  Pursuant to the requirements of the Securities Act of 1933, the
Registrant certifies that it has reasonable grounds to believe that it meets all
of the requirements for filing on Form S-8 and has duly caused this Registration
Statement  to be  signed  on its  behalf  by  the  undersigned,  thereunto  duly
authorized, in the City of Des Moines, Iowa on May 14, 2007.


                                          PRINCIPAL FINANCIAL GROUP, INC.

                                          By /s/ J. BARRY GRISWELL
                                             ----------------------------------
                                             J. Barry Griswell
                                             Chairman, President and Chief
                                             Executive Officer

Pursuant to the  requirements of the Securities Act of 1933,  this  registration
statement has been signed below by the following  persons in the  capacities and
on the date indicated.

     Dated:  May 14, 2007

By  /S/ J. BARRY GRISWELL                        By /S/ C. DANIEL GELATT, JR.
    -------------------------------              -------------------------------
     J. Barry Griswell                           C. Daniel Gelatt, Jr.
     Chairman, President, Chief                  Director
     Executive Officer and Director

By  /S/ MICHAEL H. GERSIE                        By /S/ SANDRA L. HELTON
    -------------------------------              -------------------------------
     Michael H. Gersie                           Sandra L. Helton
     Executive Vice President and Chief          Director
     Financial Officer (Principal Financial
     Officer and Chief Accounting Officer)

By  /S/ LARRY D. ZIMPLEMAN                       By /S/ WILLIAM T. KERR
    -------------------------------              -------------------------------
     Larry D. Zimpleman                          William T. Kerr
     President, Chief Operating Officer          Director
       and Director

By  /S/ BETSY J. BERNARD                         By /S/ RICHARD L. KEYSER
    -------------------------------              -------------------------------
     Betsy J. Bernard                            Richard L. Keyser
     Director                                    Director

By  /S/ JOCELYN CARTER-MILLER                    By /S/ ARJUN K. MATHRANI
    -------------------------------              -------------------------------
     Jocelyn Carter-Miller                       Arjun K. Mathrani
     Director                                    Director

By  /S/ GARY E. COSTLEY                          By /S/ ELIZABETH E. TALLETT
    -------------------------------              -------------------------------
     Gary E. Costley                             Elizabeth E. Tallett
     Director                                    Director

By  /S/ MICHAEL T. DAN                           By /S/ THERESE M. VAUGHAN
    -------------------------------              -------------------------------
     Michael T. Dan                              Therese M. Vaughan
     Director                                    Director

By  /S/ DAVID J. DRURY
    -------------------------------
     David J. Drury
     Director

                                       7
<PAGE>


                                INDEX TO EXHIBITS


 EXHIBIT NO.                                 DESCRIPTION OF EXHIBIT
 -----------                                ------------------------

4.1  Form of  Certificate  for the Common  Stock of Principal  Financial  Group,
     Inc., par value $0.01 per share, incorporated by reference to exhibit filed
     with Principal Financial Group, Inc.'s Registration  Statement on Form S-1,
     as amended (No. 333-62558).

4.1.1      Certificate of Designations of the Company's  Series A Non-Cumulative
           Perpetual  Preferred  Stock  dated  June 16,  2005,  incorporated  by
           reference to exhibit filed with  Principal  Financial  Group,  Inc.'s
           Current  Report on Form 8-K filed on June 17, 2005  (Commission  File
           No. 1-16725).

4.1.2      Certificate of Designations of the Company's  Series B Non-Cumulative
           Perpetual  Preferred  Stock,  dated June 16,  2005,  incorporated  by
           reference to exhibit filed with  Principal  Financial  Group,  Inc.'s
           Current  Report on Form 8-K filed on June 17, 2005  (Commission  File
           No. 1-16725).

4.1.3      Specimen Stock  Certificate for the Company's Series A Non-Cumulative
           Perpetual Preferred Stock, incorporated by reference to exhibit filed
           with  Principal  Financial  Group,  Inc.'s Current Report on Form 8-K
           filed on June 17, 2005 (Commission File No. 1-16725).

4.1.4      Specimen Stock  Certificate for the Company's Series B Non-Cumulative
           Perpetual Preferred Stock, incorporated by reference to exhibit filed
           with  Principal  Financial  Group,  Inc.'s Current Report on Form 8-K
           filed on June 17, 2005 (Commission File No. 1-16725).

4.1.5      Senior  Indenture,  dated as of October 11, 2006,  between  Principal
           Financial  Group,  Inc.  and  The  Bank  of  New  York,  as  Trustee,
           incorporated  by reference  to exhibit  filed with  Principal  Group,
           Inc.'s  Current  Report  on  Form  8-K  filed  on  October  16,  2006
           (Commission File No. 1-16725).

4.1.6      First  Supplemental  Indenture,  dated as of October 16, 2006,  among
           Principal Financial Group, Inc.,  Principal Financial Services,  Inc.
           and The Bank of New York,  as Trustee,  incorporated  by reference to
           exhibit filed with Principal Group, Inc.'s Current Report on Form 8-K
           filed on October 16, 2006 (Commission File No. 1-16725).

4.1.7      6.05% Senior Note  ($500,000,000) due October 15, 2036,  incorporated
           by reference to exhibit filed with  Principal  Group,  Inc.'s Current
           Report on Form 8-K filed on October  16,  2006  (Commission  File No.
           1-16725).

                                       8
<PAGE>

4.1.8      6.05% Senior Note ($100,000,000) due October 15, 2036 incorporated by
           reference  to exhibit  filed with  Principal  Group,  Inc.'s  Current
           Report on Form 8-K filed on  December  6, 2006  (Commission  File No.
           1-16725).

4.1.9      Guarantee,  dated as of October  16,  2006,  by  Principal  Financial
           Services,  Inc.  incorporated  by  reference  to  exhibit  filed with
           Principal  Group,  Inc.'s Current Report on Form 8-K filed on October
           16, 2006 (Commission File No. 1-16725).

4.2        Amended  and  Restated  Stockholder  Rights  Agreement,  dated  as of
           October 22, 2001,  incorporated  by  reference to exhibit  filed with
           Principal  Financial Group, Inc.'s Annual Report on Form 10-K for the
           year ended December 31, 2002 (Commission File No. 1-116725).

4.2.1      Amendment to the Amended and Restated Rights  Agreement,  dated as of
           January 17, 2005,  incorporated  by  reference to exhibit  filed with
           Principal  Financial Group, Inc.'s Annual Report on Form 10-K for the
           year ended December 31, 2004 (Commission File No. 1-16725).

 5*         Opinion of Karen E. Shaff

 23.1*      Consent of Ernst & Young LLP

 23.2       Consent of Karen E. Shaff (included in Exhibit 5.1).

 24*        Powers of Attorney

99.1 Principal Financial Group, Inc. 2005 Stock Incentive Plan, previously filed
     as Appendix C to Principal  Financial  Group,  Inc.'s Proxy Statement filed
     March 31, 2005 and incorporated herein by reference.

99.2 Principal Financial Group, Inc. 2005 Directors Stock Plan, previously filed
     as Appendix A to Principal  Financial  Group's Proxy  Statement filed March
     31, 2005 and incorporated herein by reference.


 *filed herewith


                                       9
<PAGE>

                                                                      Exhibit 5

[Principal Financial Group Letterhead]

May 16, 2007


Principal Financial Group, Inc.
711 High Street
Des Moines, Iowa 50392

Dear Sirs or Mesdames:

I serve as General  Counsel  to  Principal  Financial  Group,  Inc.,  a Delaware
corporation  (the  "Company"),  and deliver this opinion in connection  with the
filing by the Company of a Registration Statement on Form S-8 (the "Registration
Statement")  relating to 24,500,000  shares of the Company's  common stock,  par
value  $.01 per  share  (the  "Common  Stock"),  to be  issued  pursuant  to the
Principal  Financial  Group,  Inc. 2005 Stock  Incentive  Plan and the Principal
Financial Group, Inc. 2005 Directors Stock Plan (together, the "Plans").

I or other attorneys working under my direction have examined the originals,  or
copies certified or otherwise identified to my or said attorneys'  satisfaction,
of the Plans and such other corporate records, documents,  certificates or other
instruments as in my or said attorneys' judgment are necessary or appropriate to
enable me to render the opinion set forth below.

Based on the foregoing,  I am of the opinion that  authorized but not previously
issued shares of Common Stock which may be issued under the Plans have been duly
authorized and, when issued in accordance  with the terms of the Plans,  will be
validly issued, fully paid and non-assessable.

I  consent  to the  filing  of  this  opinion  as an  exhibit  to the  Company's
Registration  Statement. In giving such consent, I do not admit that I am within
the  category  of persons  whose  consent  is  required  under  Section 7 of the
Securities  Act of 1933 or the  rules  and  regulations  of the  Securities  and
Exchange Commission thereunder.

Sincerely,

/s/ Karen E. Shaff

Karen E. Shaff
Executive Vice President
and General Counsel


                                       10
<PAGE>


                                                                   Exhibit 23.1

Consent of Independent Registered Public Accounting Firm

We consent to the  incorporation  by reference of our reports dated February 20,
2007, in the Registration Statement (Form S-8 dated May 18, 2007 ) pertaining to
the Principal  Financial Group, Inc. 2005 Stock Incentive Plan and the Principal
Financial   Group,   Inc.  2005  Directors  Stock  Plan,  with  respect  to  the
consolidated  financial  statements and schedules of Principal  Financial Group,
Inc.,   Principal   Financial  Group,  Inc.   management's   assessment  of  the
effectiveness   of  internal   control  over   financial   reporting,   and  the
effectiveness  of  internal  control  over  financial   reporting  of  Principal
Financial  Group,  Inc.,  included in its Annual Report (Form 10-K) for the year
ended December 31, 2006, filed with the Securities and Exchange Commission.


/S/ ERNST & YOUNG
----------------------------
Des Moines, Iowa
May 17, 2007


                                       11
<PAGE>


                                                                     Exhibit 24
                                POWER OF ATTORNEY

Each person whose  signature  appears  below hereby  authorizes  and appoints J.
Barry Griswell, Michael H. Gersie, Karen E. Shaff and Joyce N. Hoffman, and each
of them, as such person's true and lawful  attorney-in-fact and agent, with full
power  of  substitution  and  resubstitution,  to sign on such  person's  behalf
individually and in each capacity stated below a Registration  Statement on Form
S-8 for the registration of 500,000 shares of Principal  Financial  Group,  Inc.
common  stock to be issued  under  the  Principal  Financial  Group,  Inc.  2005
Directors Stock Plan, and 24,000,000  shares of Principal  Financial Group, Inc.
common stock to be issued under the Principal  Financial Group,  Inc. 2005 Stock
Incentive Plan, pursuant to the Securities Exchange Act of 1934, as amended, and
any and all amendments and supplements to said  registration  statement,  and to
file the same,  with all exhibits  thereto,  and other  documents in  connection
therewith,  with the  Securities  and Exchange  Commission,  granting  unto said
attorney-in-fact and agent, and each of them, full power and authority to do and
perform each and every thing  requisite  and  necessary to be done in connection
therewith,  as fully to all  intents and  purposes  as such  person  could do in
person,  hereby ratifying and confirming all that such attorney-in-fact or agent
may lawfully do or cause to be done by virtue hereof.

Dated May 14, 2007


/S/ J. BARRY GRISWELL                      /S/ C. DANIEL GELATT, JR.
------------------------------             -------------------------------
J. Barry  Griswell                         C. Daniel  Gelatt,  Jr.
Chairman,  President and Chief             Director
Executive Officer, Director

/S/ MICHAEL H. GERSIE                      /S/ SANDRA L. HELTON
------------------------------             -------------------------------
Michael H. Gersie                          Sandra L. Helton
Executive Vice President and Chief         Director
Financial Officer

/S/ LARRY D. ZIMPLEMAN                     /S/ WILLIAM T. KERR
------------------------------             -------------------------------
Larry D. Zimpleman                         William T. Kerr
President, Chief Operating Officer         Director
and Director

/S/ BETSY J. BERNARD                       /S/ RICHARD L. KEYSER
------------------------------             -------------------------------
Betsy J. Bernard                           Richard L. Keyser
Director                                   Director

/S/ JOCELYN CARTER-MILLER                  /S/ ARJUN K. MATHRANI
------------------------------             -------------------------------
Jocelyn Carter-Miller                      Arjun K. Mathrani
Director                                   Director

/S/ GARY E. COSTLEY                        /S/ ELIZABETH E. TALLETT
------------------------------             -------------------------------
Gary E. Costley                            Elizabeth E. Tallett
Director                                   Director

/S/ MICHAEL T. DAN                         /S/ THERESE M. VAUGHAN
------------------------------             -------------------------------
Michael T. Dan                             Therese M. Vaughan
Director                                   Director

/S/ DAVID J. DRURY
------------------------------
David J. Drury
Director



                                       12
<PAGE>
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As filed with the Securities and Exchange Commission on May 18, 2007

                                                     Registration No. 333-____
     =====================================================================

                                  UNITED STATES
                       SECURITIES AND EXCHANGE COMMISSION
                             WASHINGTON, D.C. 20549

                                 ---------------

                                    FORM S-8

                             REGISTRATION STATEMENT
                                      UNDER
                           THE SECURITIES ACT OF 1933

                                ----------------

                         PRINCIPAL FINANCIAL GROUP, INC.
             (Exact name of registrant as specified in its charter)

        DELAWARE                                              42-1520346
(State or other jurisdiction of                             (I.R.S. Employer
 incorporation or organization)                            Identification No.)

                                 711 HIGH STREET
                             DES MOINES, IOWA 50392
                    (Address of Principal Executive Offices)

            PRINCIPAL FINANCIAL GROUP, INC. 2005 STOCK INCENTIVE PLAN
            PRINCIPAL FINANCIAL GROUP, INC. 2005 DIRECTORS STOCK PLAN
                            (Full title of the Plans)

                              KAREN E. SHAFF, ESQ.
                  EXECUTIVE VICE PRESIDENT AND GENERAL COUNSEL
                         PRINCIPAL FINANCIAL GROUP, INC.
                                 711 HIGH STREET
                             DES MOINES, IOWA 50392
                                 (515) 247-5111
            (Name, address and telephone number of agent for service)

     =====================================================================

                                       1
CALCULATION OF REGISTRATION FEE

-------------------------------------------------------------------------------------------------------------
Proposed            Proposed
Title                                              maximum             maximum
Securities to be                Amount to be       offering price per  aggregate          Amount of
registered                      registered         share(2)            offering price(2)  registration fee
-------------------------------------------------------------------------------------------------------------
Common Stock,
par value $.01
per share                       24,500,000(1)       $60.60             $1,484,700,000.00  $45,580.29
-------------------------------------------------------------------------------------------------------------
(1)      Consists  of shares  of  common  stock to be  offered  pursuant  to the
         Principal  Financial  Group,  Inc.  2005 Stock  Incentive  Plan and the
         Principal  Financial  Group,  Inc.  2005  Directors  Stock  Plan.  Such
         indeterminate  number of additional  shares as may be issuable pursuant
         to the  recapitalization  provisions  under the employee  benefit plans
         described herein is hereby also registered.

(2)      Estimated  solely for the purposes of determining the  registration fee
         pursuant  to the  provisions  of Rules  457(c)  and  457(h)  under  the
         Securities  Act  based on the  average  of high and low  prices  of the
         Common Stock as reported on the New York Stock Exchange  Composite Tape
         on May 16, 2007, which was $60.60.

                                       2
PART II

               INFORMATION REQUIRED IN THE REGISTRATION STATEMENT

ITEM 3.  INCORPORATION OF DOCUMENTS BY REFERENCE

The following documents are incorporated by reference:

     (a)  Principal  Financial Group,  Inc.'s Annual Report on Form 10-K for the
          year ended December 31, 2006 (filed February 28, 2007)

     (b)  Principal  Financial  Group,  Inc.'s Quarterly Report on Form 10-Q for
          the quarter ended March 31, 2007 (filed May 2, 2007)

     (c)   Principal  Financial  Group's  Current  Reports  on Form  8-K  dated:
           December  31,  2006 (filed  January 3, 2007)  January 18, 2007 (filed
           January 18, 2007) February 5, 2007 (filed February 6, 2007) April 23,
           2007 (filed April 23, 2007) April 30, 2007 (filed May 1, 2007)

     (d) Amendment  No. 4 to  Principal  Financial  Group,  Inc.'s  Registration
         Statement on Form S- 1, file number 333-62558,  and related Prospectus,
         as filed with the  Securities  and Exchange  Commission  on October 22,
         2001.  Information relating to Principal Financial Group, Inc.'s common
         stock is set forth under the caption  "Description of Capital Stock and
         Change of Control Related Provisions" in the Registration  Statement on
         Form S-1.

In addition, all documents subsequently filed by Principal Financial Group, Inc.
pursuant to Sections 13(a),  13(c), 14 and 15(d) of the Securities  Exchange Act
of 1934, prior to the filing of a post-effective  amendment which indicates that
all securities offered hereby have been sold or which deregisters all securities
then remaining  unsold,  shall be deemed to be incorporated by reference in this
Registration  Statement  and to be a part  hereof  from the date of filing  such
documents.

Any statement contained in a document  incorporated or deemed to be incorporated
by reference herein shall be deemed to be modified or superseded for purposes of
this Registration  Statement to the extent that a statement contained herein (or
in any other subsequently filed document which also is incorporated or deemed to
be incorporated by reference herein) modifies or supersedes such statement.  Any
such  statement  so modified  or  superseded  shall not be deemed,  except as so
modified or superseded, to constitute a part of this Registration Statement.

ITEM 4.  DESCRIPTION OF SECURITIES

Not applicable.

                                       3
ITEM 5.  INTERESTS OF NAMED EXPERTS AND COUNSEL

The validity of the securities being offered under this  Registration  Statement
are  being  passed  upon  for the  Registrant  by  Karen  E.  Shaff,  Esq.,  the
Registrant's Executive Vice President and General Counsel. Ms. Shaff is eligible
to receive shares under the Principal Financial Group, Inc. 2005 Stock Incentive
Plan, whose shares are subject to this Registration Statement.

ITEM 6.  INDEMNIFICATION OF DIRECTORS AND OFFICERS

Our  directors  and  officers may be  indemnified  against  liabilities,  fines,
penalties  and claims  imposed upon or asserted  against them as provided in the
Delaware  General  Corporation  Law and our  certificate  of  incorporation  and
by-laws.  Such  indemnification  covers  all costs and  expenses  incurred  by a
director or officer in his or her capacity as such. The board of directors, by a
majority  vote  of  a  quorum  of  disinterested  directors  or,  under  certain
circumstances,  independent  counsel  appointed by the board of directors,  must
determine that the director or officer seeking indemnification was not guilty of
willful  misconduct  or a knowing  violation of criminal  law. In addition,  the
Delaware General Corporation Law and our certificate of incorporation may, under
certain  circumstances,  eliminate  the liability of directors and officers in a
stockholder or derivative proceeding.

If the person  involved  is not a director  or  officer of  Principal  Financial
Group, Inc., the board of directors may cause Principal Financial Group, Inc. to
indemnify,  to the same extent  allowed for our  directors  and  officers,  such
person  who was or is a party to a  proceeding  by reason of the fact that he or
she is or was our  employee  or agent,  or is or was serving at our request as a
director, officer, employee or agent of another corporation,  partnership, joint
venture, trust, employee benefit plan or other enterprise.

We have  policies  in force and  effect to insure  our  directors  and  officers
against such losses which they or any of them will become  legally  obligated to
pay by reason of any  actual or  alleged  error or  misstatement  or  misleading
statement or act or omission or neglect or breach of duty by such  directors and
officers in the discharge of their duties, individually or collectively, or as a
result of any  matter  claimed  against  them  solely  by reason of their  being
directors  or  officers.  Such  coverage  is limited by the  specific  terms and
provisions of the insurance policies.

ITEM 7.  EXEMPTION FROM REGISTRATION CLAIMED

Not applicable.

ITEM 8.  EXHIBITS

                                       4
An Exhibit Index, containing a list of all exhibits filed with this Registration
Statement, is included on page nine.

ITEM 9.  UNDERTAKINGS

          (a)  Rule 415 Offering. The undersigned Registrant hereby undertakes:

          (1)  To file,  during  any  period in which  offers or sales are being
               made, a post-effective amendment to this Registration Statement:

               (i)  To include any  Prospectus  required by section  10(a)(3) of
                    the  Securities  Act of  1933,  unless  the  information  is
                    contained  in  periodic  reports  filed  by  the  Registrant
                    pursuant to section 13 or section  15(d) of the Exchange Act
                    of  1934  that  are   incorporated   by   reference  in  the
                    Registration Statement;

               (ii) To reflect  in the  Prospectus  any facts or events  arising
                    after the effective date of the  Registration  Statement (or
                    the most recent  post-effective  amendment  thereof)  which,
                    individually  or in the  aggregate,  represent a fundamental
                    change  in the  information  set  forth in the  Registration
                    Statement,  unless the  information is contained in periodic
                    reports  filed by the  Registrant  pursuant to section 13 or
                    15(d) of the Exchange Act of 1934 that are  incorporated  by
                    reference in the Registration Statement;

               (iii) To include any  material  information  with  respect to the
                    plan  of  distribution  not  previously   disclosed  in  the
                    Registration  Statement  or  any  material  change  to  such
                    information in the Registration Statement.

          (2)  That,  for the purpose of  determining  any  liability  under the
               Securities  Act,  each  such  post-effective  amendment  shall be
               deemed  to  be a  new  registration  statement  relating  to  the
               securities  offered therein,  and the offering of such securities
               at that time shall be deemed to be the initial bona fide offering
               thereof.

          (3)  To  remove  from   registration  by  means  of  a  post-effective
               amendment any of the  securities  being  registered  which remain
               unsold at the termination of the offering.

          (b)  Subsequent  Exchange Act Documents.  The  undersigned  Registrant
               hereby undertakes that, for purposes of determining any liability
               under the Securities Act, each filing of the Registrant's  annual
               report pursuant to section 13(a) or section 15(d) of the Exchange
               Act (and,  where  applicable,  each filing of an employee benefit
               plan's  annual  report  pursuant to section 15(d) of the Exchange
               Act)  that  is  incorporated  by  reference  in the  Registration
               Statement  shall be  deemed  to be a new  registration  statement
               relating to the securities  offered therein,  and the offering of
               such  securities  at that time shall be deemed to be the  initial
               bona fide offering thereof.

          (c)  Indemnification.   Insofar  as  indemnification  for  liabilities
               arising under the  Securities  Act may be permitted to directors,
               officers and  controlling  persons of the Registrant  pursuant to

                                       5
the foregoing provisions,  or otherwise,  the Registrant has been
               advised  that  in the  opinion  of the  Securities  and  Exchange
               Commission  such  indemnification  is  against  public  policy as
               expressed in the Securities Act and is, therefore, unenforceable.
               In the  event  that a  claim  for  Indemnification  against  such
               liabilities (other than the payment by the Registrant of expenses
               incurred or paid by a director,  officer or controlling person of
               the Registrant in the successful  defense of any action,  suit or
               proceeding) is asserted by such director,  officer or controlling
               person in connection with the securities  being  registered,  the
               Registrant will,  unless in the opinion of its counsel the matter
               has been settled by controlling  precedent,  submit to a court of
               appropriate    jurisdiction    the    question    whether    such
               indemnification  by it is against  public  policy as expressed in
               the Securities Act and will be governed by the final adjudication
               of such issue.

                                       6
SIGNATURES

The Registrant.  Pursuant to the requirements of the Securities Act of 1933, the
Registrant certifies that it has reasonable grounds to believe that it meets all
of the requirements for filing on Form S-8 and has duly caused this Registration
Statement  to be  signed  on its  behalf  by  the  undersigned,  thereunto  duly
authorized, in the City of Des Moines, Iowa on May 14, 2007.

                                          PRINCIPAL FINANCIAL GROUP, INC.

                                          By /s/ J. BARRY GRISWELL
                                             ----------------------------------
                                             J. Barry Griswell
                                             Chairman, President and Chief
                                             Executive Officer

Pursuant to the  requirements of the Securities Act of 1933,  this  registration
statement has been signed below by the following  persons in the  capacities and
on the date indicated.

     Dated:  May 14, 2007

By  /S/ J. BARRY GRISWELL                        By /S/ C. DANIEL GELATT, JR.
    -------------------------------              -------------------------------
     J. Barry Griswell                           C. Daniel Gelatt, Jr.
     Chairman, President, Chief                  Director
     Executive Officer and Director

By  /S/ MICHAEL H. GERSIE                        By /S/ SANDRA L. HELTON
    -------------------------------              -------------------------------
     Michael H. Gersie                           Sandra L. Helton
     Executive Vice President and Chief          Director
     Financial Officer (Principal Financial
     Officer and Chief Accounting Officer)

By  /S/ LARRY D. ZIMPLEMAN                       By /S/ WILLIAM T. KERR
    -------------------------------              -------------------------------
     Larry D. Zimpleman                          William T. Kerr
     President, Chief Operating Officer          Director
       and Director

By  /S/ BETSY J. BERNARD                         By /S/ RICHARD L. KEYSER
    -------------------------------              -------------------------------
     Betsy J. Bernard                            Richard L. Keyser
     Director                                    Director

By  /S/ JOCELYN CARTER-MILLER                    By /S/ ARJUN K. MATHRANI
    -------------------------------              -------------------------------
     Jocelyn Carter-Miller                       Arjun K. Mathrani
     Director                                    Director

By  /S/ GARY E. COSTLEY                          By /S/ ELIZABETH E. TALLETT
    -------------------------------              -------------------------------
     Gary E. Costley                             Elizabeth E. Tallett
     Director                                    Director

By  /S/ MICHAEL T. DAN                           By /S/ THERESE M. VAUGHAN
    -------------------------------              -------------------------------
     Michael T. Dan                              Therese M. Vaughan
     Director                                    Director

By  /S/ DAVID J. DRURY
    -------------------------------
     David J. Drury
     Director

                                       7
INDEX TO EXHIBITS

 EXHIBIT NO.                                 DESCRIPTION OF EXHIBIT
 -----------                                ------------------------

4.1  Form of  Certificate  for the Common  Stock of Principal  Financial  Group,
     Inc., par value $0.01 per share, incorporated by reference to exhibit filed
     with Principal Financial Group, Inc.'s Registration  Statement on Form S-1,
     as amended (No. 333-62558).

4.1.1      Certificate of Designations of the Company's  Series A Non-Cumulative
           Perpetual  Preferred  Stock  dated  June 16,  2005,  incorporated  by
           reference to exhibit filed with  Principal  Financial  Group,  Inc.'s
           Current  Report on Form 8-K filed on June 17, 2005  (Commission  File
           No. 1-16725).

4.1.2      Certificate of Designations of the Company's  Series B Non-Cumulative
           Perpetual  Preferred  Stock,  dated June 16,  2005,  incorporated  by
           reference to exhibit filed with  Principal  Financial  Group,  Inc.'s
           Current  Report on Form 8-K filed on June 17, 2005  (Commission  File
           No. 1-16725).

4.1.3      Specimen Stock  Certificate for the Company's Series A Non-Cumulative
           Perpetual Preferred Stock, incorporated by reference to exhibit filed
           with  Principal  Financial  Group,  Inc.'s Current Report on Form 8-K
           filed on June 17, 2005 (Commission File No. 1-16725).

4.1.4      Specimen Stock  Certificate for the Company's Series B Non-Cumulative
           Perpetual Preferred Stock, incorporated by reference to exhibit filed
           with  Principal  Financial  Group,  Inc.'s Current Report on Form 8-K
           filed on June 17, 2005 (Commission File No. 1-16725).

4.1.5      Senior  Indenture,  dated as of October 11, 2006,  between  Principal
           Financial  Group,  Inc.  and  The  Bank  of  New  York,  as  Trustee,
           incorporated  by reference  to exhibit  filed with  Principal  Group,
           Inc.'s  Current  Report  on  Form  8-K  filed  on  October  16,  2006
           (Commission File No. 1-16725).

4.1.6      First  Supplemental  Indenture,  dated as of October 16, 2006,  among
           Principal Financial Group, Inc.,  Principal Financial Services,  Inc.
           and The Bank of New York,  as Trustee,  incorporated  by reference to
           exhibit filed with Principal Group, Inc.'s Current Report on Form 8-K
           filed on October 16, 2006 (Commission File No. 1-16725).

4.1.7      6.05% Senior Note  ($500,000,000) due October 15, 2036,  incorporated
           by reference to exhibit filed with  Principal  Group,  Inc.'s Current
           Report on Form 8-K filed on October  16,  2006  (Commission  File No.
           1-16725).

                                       8
4.1.8      6.05% Senior Note ($100,000,000) due October 15, 2036 incorporated by
           reference  to exhibit  filed with  Principal  Group,  Inc.'s  Current
           Report on Form 8-K filed on  December  6, 2006  (Commission  File No.
           1-16725).

4.1.9      Guarantee,  dated as of October  16,  2006,  by  Principal  Financial
           Services,  Inc.  incorporated  by  reference  to  exhibit  filed with
           Principal  Group,  Inc.'s Current Report on Form 8-K filed on October
           16, 2006 (Commission File No. 1-16725).

4.2        Amended  and  Restated  Stockholder  Rights  Agreement,  dated  as of
           October 22, 2001,  incorporated  by  reference to exhibit  filed with
           Principal  Financial Group, Inc.'s Annual Report on Form 10-K for the
           year ended December 31, 2002 (Commission File No. 1-116725).

4.2.1      Amendment to the Amended and Restated Rights  Agreement,  dated as of
           January 17, 2005,  incorporated  by  reference to exhibit  filed with
           Principal  Financial Group, Inc.'s Annual Report on Form 10-K for the
           year ended December 31, 2004 (Commission File No. 1-16725).

 5*         Opinion of Karen E. Shaff

 23.1*      Consent of Ernst & Young LLP

 23.2       Consent of Karen E. Shaff (included in Exhibit 5.1).

 24*        Powers of Attorney

99.1 Principal Financial Group, Inc. 2005 Stock Incentive Plan, previously filed
     as Appendix C to Principal  Financial  Group,  Inc.'s Proxy Statement filed
     March 31, 2005 and incorporated herein by reference.

99.2 Principal Financial Group, Inc. 2005 Directors Stock Plan, previously filed
     as Appendix A to Principal  Financial  Group's Proxy  Statement filed March
     31, 2005 and incorporated herein by reference.

 *filed herewith

                                       9
Exhibit 5

[Principal Financial Group Letterhead]

May 16, 2007

Principal Financial Group, Inc.
711 High Street
Des Moines, Iowa 50392

Dear Sirs or Mesdames:

I serve as General  Counsel  to  Principal  Financial  Group,  Inc.,  a Delaware
corporation  (the  "Company"),  and deliver this opinion in connection  with the
filing by the Company of a Registration Statement on Form S-8 (the "Registration
Statement")  relating to 24,500,000  shares of the Company's  common stock,  par
value  $.01 per  share  (the  "Common  Stock"),  to be  issued  pursuant  to the
Principal  Financial  Group,  Inc. 2005 Stock  Incentive  Plan and the Principal
Financial Group, Inc. 2005 Directors Stock Plan (together, the "Plans").

I or other attorneys working under my direction have examined the originals,  or
copies certified or otherwise identified to my or said attorneys'  satisfaction,
of the Plans and such other corporate records, documents,  certificates or other
instruments as in my or said attorneys' judgment are necessary or appropriate to
enable me to render the opinion set forth below.

Based on the foregoing,  I am of the opinion that  authorized but not previously
issued shares of Common Stock which may be issued under the Plans have been duly
authorized and, when issued in accordance  with the terms of the Plans,  will be
validly issued, fully paid and non-assessable.

I  consent  to the  filing  of  this  opinion  as an  exhibit  to the  Company's
Registration  Statement. In giving such consent, I do not admit that I am within
the  category  of persons  whose  consent  is  required  under  Section 7 of the
Securities  Act of 1933 or the  rules  and  regulations  of the  Securities  and
Exchange Commission thereunder.

Sincerely,

/s/ Karen E. Shaff

Karen E. Shaff
Executive Vice President
and General Counsel

                                       10
Exhibit 23.1

Consent of Independent Registered Public Accounting Firm

We consent to the  incorporation  by reference of our reports dated February 20,
2007, in the Registration Statement (Form S-8 dated May 18, 2007 ) pertaining to
the Principal  Financial Group, Inc. 2005 Stock Incentive Plan and the Principal
Financial   Group,   Inc.  2005  Directors  Stock  Plan,  with  respect  to  the
consolidated  financial  statements and schedules of Principal  Financial Group,
Inc.,   Principal   Financial  Group,  Inc.   management's   assessment  of  the
effectiveness   of  internal   control  over   financial   reporting,   and  the
effectiveness  of  internal  control  over  financial   reporting  of  Principal
Financial  Group,  Inc.,  included in its Annual Report (Form 10-K) for the year
ended December 31, 2006, filed with the Securities and Exchange Commission.

/S/ ERNST & YOUNG
----------------------------
Des Moines, Iowa
May 17, 2007

                                       11
Exhibit 24
                                POWER OF ATTORNEY

Each person whose  signature  appears  below hereby  authorizes  and appoints J.
Barry Griswell, Michael H. Gersie, Karen E. Shaff and Joyce N. Hoffman, and each
of them, as such person's true and lawful  attorney-in-fact and agent, with full
power  of  substitution  and  resubstitution,  to sign on such  person's  behalf
individually and in each capacity stated below a Registration  Statement on Form
S-8 for the registration of 500,000 shares of Principal  Financial  Group,  Inc.
common  stock to be issued  under  the  Principal  Financial  Group,  Inc.  2005
Directors Stock Plan, and 24,000,000  shares of Principal  Financial Group, Inc.
common stock to be issued under the Principal  Financial Group,  Inc. 2005 Stock
Incentive Plan, pursuant to the Securities Exchange Act of 1934, as amended, and
any and all amendments and supplements to said  registration  statement,  and to
file the same,  with all exhibits  thereto,  and other  documents in  connection
therewith,  with the  Securities  and Exchange  Commission,  granting  unto said
attorney-in-fact and agent, and each of them, full power and authority to do and
perform each and every thing  requisite  and  necessary to be done in connection
therewith,  as fully to all  intents and  purposes  as such  person  could do in
person,  hereby ratifying and confirming all that such attorney-in-fact or agent
may lawfully do or cause to be done by virtue hereof.

Dated May 14, 2007

/S/ J. BARRY GRISWELL                      /S/ C. DANIEL GELATT, JR.
------------------------------             -------------------------------
J. Barry  Griswell                         C. Daniel  Gelatt,  Jr.
Chairman,  President and Chief             Director
Executive Officer, Director

/S/ MICHAEL H. GERSIE                      /S/ SANDRA L. HELTON
------------------------------             -------------------------------
Michael H. Gersie                          Sandra L. Helton
Executive Vice President and Chief         Director
Financial Officer

/S/ LARRY D. ZIMPLEMAN                     /S/ WILLIAM T. KERR
------------------------------             -------------------------------
Larry D. Zimpleman                         William T. Kerr
President, Chief Operating Officer         Director
and Director

/S/ BETSY J. BERNARD                       /S/ RICHARD L. KEYSER
------------------------------             -------------------------------
Betsy J. Bernard                           Richard L. Keyser
Director                                   Director

/S/ JOCELYN CARTER-MILLER                  /S/ ARJUN K. MATHRANI
------------------------------             -------------------------------
Jocelyn Carter-Miller                      Arjun K. Mathrani
Director                                   Director

/S/ GARY E. COSTLEY                        /S/ ELIZABETH E. TALLETT
------------------------------             -------------------------------
Gary E. Costley                            Elizabeth E. Tallett
Director                                   Director

/S/ MICHAEL T. DAN                         /S/ THERESE M. VAUGHAN
------------------------------             -------------------------------
Michael T. Dan                             Therese M. Vaughan
Director                                   Director

/S/ DAVID J. DRURY
------------------------------
David J. Drury
Director

                                       12