March 1, 2010 

VIA EDGAR 

Ms. Rebecca Marquigny 

Senior Counsel 

Division of Investment Management 

Securities and Exchange Commission 

100 F Street, NE 

Washington, D.C. 20549-4644 

RE:	Principal Life Insurance Company Separate Account B
	Principal Investment Plus Variable Annuity Contract
	File Numbers 333-116220 and 811-02091
	16th Post-Effective Amendment to the Registration Statement on Form N-4

Dear Ms. Marquigny: 

Enclosed herein is post-effective amendment no. 16 to registration statement on Form N- 

4 for Principal Investment Plus Variable Annuity Contract. This 16^th amendment is being 

filed pursuant to paragraph (a) of Rule 485. 

We understand that the registrant is responsible for the accuracy and adequacy of the 

disclosure in the filing and that staff comments or our changes to the disclosure in 

response to the staff comments do not foreclose the Commission from taking any action 

with respect to the filing. In addition, the registrant may not assert staff comments as a 

defense in any proceeding initiated by the Commission or any person under the federal 

securities laws of the United States. 

Please contact me if you have any questions concerning this filing. 

Sincerely, 

/s/ Jeffrey M. Pierick 

Jeffrey M. Pierick 

Counsel 

711 High Street 

Des Moines, Iowa 503092-0300 

(515) 362-2384 (office) 

(866) 496-6527 (facsimile) 

pierick.jeff@principal.com 

JMP/kcr 

Enclosure