Pricing Supplement Dated April 18, 2008	 	Filed Pursuant to Rule 424(b)(2)	
(To Prospectus dated November 21, 2007, and	 	Registration Statement Nos. 333-147181	
Prospectus Supplement dated November 21, 2007)	 	and 333-147181-01	
 	 	CUSIP: 74254PYF3	

Principal Life Insurance Company
Secured Medium-Term Notes (that are also Asset-Backed Securities)
Issued Through and Obligations of
Principal Life Income Fundings Trust 37 (the “Trust” and the “Issuing Entity”)
     The description of this pricing supplement of the particular terms of the Secured Medium-Term Notes offered hereby, and the Funding Agreement (specified below) issued by Principal Life Insurance Company (“Principal Life”) to the Trust, the payment obligations of which are fully and unconditionally guaranteed by the Guarantee (specified below) issued by Principal Financial Group, Inc. to the Trust, supplements the description of the general terms and provisions of the notes, the funding agreements and the guarantees set forth in the accompanying prospectus and prospectus supplement, to which reference is hereby made.
1. The Notes
 	 	 	 	 	 	 	
Principal Amount:	 	$300,000,000 	 	Purchasing Agent(s) Discount:	 	0.166% 	
Issue Price:	 	99.513% 	 	Original Issue Date:	 	April 25, 2008	
Net Proceeds to the Trust:	 	$298,539,000 	 	Stated Maturity Date:	 	April 27, 2015	
 	 	 	
Specified Currency:	 	U.S. Dollars	
 	 	 	
Interest Payment Dates:	 	     April 27 and October 27 of each year	
 	 	 	
Initial Interest Payment Date:	 	     October 27, 2008	
 	 	 	
Regular Record Date:	 	15 calendar days prior to the Interest Payment Date	
Type of Interest Rate: þ Fixed Rate o Floating Rate
          Fixed Rate Notes: þ Yes o No. If, Yes,
               Interest Rate: 5.550%
          Floating Rate Notes: o Yes þ No. If, Yes,
               Regular Floating Rate Notes: o Yes o No. If, Yes,
Interest Rate:
Interest Rate Basis(es):
               Floating Rate/Fixed Rate Note: o Yes o No. If, Yes,
Floating Interest Rate:
Interest Rate Basis(es):
Fixed Interest Rate:
Fixed Rate Commencement Date:

 

               Inverse Floating Rate Note: o Yes o No. If, Yes,
Fixed Interest Rate:
Floating Interest Rate:
Interest Rate Basis(es):
               Initial Interest Rate, if any:
               Initial Interest Rate, if any:
               Initial Interest Reset Date:
               Interest Rate Basis(es). Check all that apply:
 	 	 	 	 	
 	 	o CD Rate	 	o Commercial Paper Rate	
 	 	o CMT Rate	 	o Eleventh District Cost of Funds Rate	
 	 	o Constant Maturity Swap Rate	 	o Federal Fund Open Rate	
 	 	o LIBOR	 	o Federal Funds Rate	
 	 	o EURIBOR	 	o Treasury Rate	
 	 	o Prime Rate	 	o Other	
If LIBOR: o LIBOR Reuters
LIBOR Currency:
If CMT Rate:
Designated Reuters Page:
If FEDCMT: o Weekly Average o Monthly Average
Designated CMT Maturity Index:
               Index Maturity:
               Spread (+/-):
               Spread Multiplier:
               Interest Reset Date(s):
               Interest Rate Determination Date(s):
               Maximum Interest Rate, if any:
               Minimum Interest Rate, if any:
Calculation Agent: Citibank, N.A.
Exchange Rate Agent: Not applicable
Computation of Interest (not applicable unless different than as specified in the prospectus and prospectus supplement):
Day Count Convention (not applicable unless different than as specified in the prospectus and prospectus supplement):
Amortizing Notes: o Yes þ No. If, Yes,
               Amortizing Schedule:
               Additional/ Other Terms
Discount Note: o Yes þ No. If, Yes,
               Total Amount of Discount:
               Initial Accrual Period of Discount:
               Additional/Other Terms:
Redemption Provisions: o Yes þ No. If, Yes,
               Initial Redemption Date:
               Initial Redemption Percentage:
               Annual Redemption Percentage Reduction (if any):
               Redemption o In whole only and not in part
                                      o May be in whole or in part
               Additional/Other Terms:
Repayment: o Yes þ No. If Yes,

 

               Repayment Date(s):
               Repayment Price:
               Repayment: o In whole only and not in part
   o May be in whole or in part
               Additional/Other Terms:
Sinking Fund (not applicable unless specified):
Additional Amounts to be Paid for Withholding Tax (not applicable unless specified):
Securities Exchange Listing: o Yes þ No. If Yes, Name of Exchange:
Authorized Denominations: $1,000
Ratings: The Notes issued under the Program are rated AA by Standard & Poor’s Ratings Services, a division of The McGraw-Hill Companies, Inc. (“S&P”). Principal Life expects the Notes to be rated Aa2 by Moody’s Investors Service, Inc. (“Moody’s”).
Purchasing Agent(s) Purchasing Notes as Principal: þ Yes o No. If Yes,
 	 	 	 	 	
Purchasing Agent(s)	 	Principal Amount	
Banc of America Securities LLC	 	$	100,000,000	 	
Deutsche Bank Securities Inc.	 	$	100,000,000	 	
J.P. Morgan Securities Inc.	 	$	100,000,000	 	

Total:	 	$	300,000,000	 	
Purchasing Agent(s) Acting as Agent: o Yes þ No. If Yes,
 	 	 	 	 	
Purchasing Agent(s)	 	Principal Amount	
 	 	 	 	 	
Total:	 	 	 	 	
State of Organization of Trust: New York
Additional/Other Terms:
Special Tax Considerations:
2. The Funding Agreement
 	 	 	
Funding Agreement Issuer:	 	Principal Life Insurance Company	
 	 	 	
Funding Agreement No.:	 	4-55455 	
 	 	 	
Deposit Amount:	 	$300,000,015 	
 	 	 	
Net Deposit:	 	$298,539,000 	
 	 	 	
Effective Date:	 	April 25, 2008	
 	 	 	
Stated Maturity Date:	 	April 27, 2015	
 	 	 	
Specified Currency:	 	U.S. Dollars	
 	 	 	
Interest Payment Dates:	 	April 27 and October 27 of each year	
 	 	 	
Initial Interest Payment Date:	 	October 27, 2008	
 	 	 	
Type of Interest Rate:	 	þ Fixed Rate o Floating Rate	
               Fixed Rate Funding Agreement: þ Yes o No. If, Yes,

 

               Interest Rate: 5.550%
               Floating Rate Funding Agreement: o Yes þ No. If, Yes,
Regular Floating Rate Funding Agreement: o Yes o No. If Yes,
Interest Rate:
Interest Rate Basis(es):
Floating Rate/Fixed Rate Funding Agreement: o Yes o No. If, Yes,
Floating Interest Rate:
Interest Rate Basis(es):
Fixed Interest Rate:
Fixed Rate Commencement Date:
Inverse Floating Rate Funding Agreement: o Yes o No. If, Yes,
Fixed Interest Rate:
Floating Interest Rate:
Interest Rate Basis(es):
               Initial Interest Rate, if any:
               Initial Interest Reset Date:
               Interest Rate Basis(es). check all that apply
 	 	 	 	 	
 	 	o CD Rate	 	o Commercial Paper Rate	
 	 	o CMT Rate	 	o Eleventh District Cost of Funds Rate	
 	 	o Constant Maturity Swap Rate	 	o Federal Funds Open Rate	
 	 	o LIBOR	 	o Federal Funds Rate	
 	 	o EURIBOR	 	o Treasury Rate	
 	 	o Prime Rate	 	o Other (See Attached)	
If LIBOR: o LIBOR Reuters
LIBOR Currency:
If CMT Rate:
Designated Reuters Page:
If FEDCMT: o Weekly Average o Monthly Average
Designated CMT Maturity Index:
               Index Maturity:
               Spread (+/-):
               Spread Multiplier:
               Interest Reset Date(s):
               Interest Rate Determination Date(s):
               Maximum Interest Rate, if any:
               Minimum Interest Rate, if any:
Calculation of Interest (not applicable unless different than as specified in the prospectus and prospectus supplement):
Day Count Convention (not applicable unless different than as specified in the prospectus and prospectus supplement):
Amortizing Funding Agreement: o Yes þ No. If Yes,
               Amortizing Schedule
               Additional/Other Terms
Discount Funding Agreement: o Yes þ No. If, Yes,
               Total Amount of Discount:
               Initial Accrual Period of Discount:
               Additional/Other Terms:

 

Redemption Provisions: o Yes þ No. If, Yes,
               Initial Redemption Date:
               Initial Redemption Percentage:
               Annual Redemption Percentage Reduction (if any):
               Redemption: o In whole only and not in part
    o May be in whole or in part
               Additional/Other Terms:
Repayment: o Yes þ No. If, Yes,
               Repayment Date(s):
               Repayment Price:
               Repayment: o In whole only and not in part
   o May be in whole or in part
               Additional/Other Terms:
Sinking Fund (not applicable unless specified):
Additional Amounts to be Paid For Withholding Tax (not applicable unless specified):
Ratings: The Funding Agreement issued under the Program is rated AA by S&P. Principal Life expects the Funding Agreement to be rated Aa2 by Moody’s.
Additional/Other Terms if any:
Special Tax Considerations:
3. The Guarantee
Guarantee Issuer: Principal Financial Group, Inc.
Effective Date: April 25, 2008
Additional/Other Terms if any: