As Filed with the Securities and Exchange Commission on November 17, 2006

REGISTRATION NO. 333-83516

811-05846

SECURITIES AND EXCHANGE COMMISSION

WASHINGTON, D.C. 20549

FORM N-4

REGISTRATION STATEMENT UNDER THE SECURITIES ACT OF 1933

Post Effective Amendment No. 20

and

REGISTRATION STATEMENT UNDER THE INVESTMENT COMPANY ACT OF 1940

Amendment No. 75

SUN LIFE OF CANADA (U.S.) VARIABLE ACCOUNT F

(Exact Name of Registrant)

SUN LIFE ASSURANCE COMPANY OF CANADA (U.S.)

(Name of Depositor)

One Sun Life Executive Park

Wellesley Hills, Massachusetts 02481

(Address of Depositor's Principal Executive Offices)

Depositor's Telephone Number, including Area Code: (781) 237-6030

Bruce A. Teichner, Assistant Vice President and Senior Counsel

Sun Life Assurance Company of Canada (U.S.)

One Sun Life Executive Park, SC 1335

Wellesley Hills, Massachusetts 02481

(Name and Address of Agent for Service)

Copies of Communications to:

Thomas C. Lauerman, Esq.

Jorden Burt LLP

1025 Thomas Jefferson Street, N.W.

Suite 400 East

Washington, D.C. 20007-0805

It is proposed that this filing will become effective (check appropriate box)

£ immediately upon filing pursuant to paragraph (b) of Rule 485

R on December 15, 2006 pursuant to paragraph (b) of Rule 485

£ 60 days after filing pursuant to paragraph (a)(1) of Rule 485

£ on (date) pursuant to paragraph (a)(1) of Rule 485.

If appropriate, check the following box:

R this post-effective amendment designates a new effective date for a previously filed post-effective amendment.

No filing fee is due because an indefinite amount of securities is deemed to have been registered in reliance on Section 24(f) of the Investment Company Act of 1940.

Pursuant to Rule 485 (b)(1)(iii) of the Securities Act of 1933, the sole purpose of this Post-Effective Amendment No. 20 is to delay the effective date of the Post-Effective Amendment No. 19, which was filed on or about September 22, 2006. The Parts A, B and C of Post-Effective Amendment No. 19 are hereby incorporated by reference and this amendment does not delete or supersede any other prospectus or information that is part of the registration statement.

SIGNATURES

As required by the Securities Act of 1933 and the Investment Company Act of 1940, the Registrant certifies that it meets all of the requirements of Securities Act Rule 485(b) for effectiveness of this Post-Effective Amendment to the Registration Statement and has caused this Post-Effective Amendment to the Registration Statement to be signed on its behalf, in the Town of Wellesley Hills, and Commonwealth of Massachusetts on this 17th day of November, 2006.

SUN LIFE OF CANADA (U.S.) VARIABLE ACCOUNT F

(Registrant)

SUN LIFE ASSURANCE COMPANY OF CANADA (U.S.)

(Depositor)

By: /s/ Robert C. Salipante*

Robert C. Salipante

President and Director

*By:	/s/ Sandra M. DaDalt
	Sandra M. DaDalt
	Assistant Vice President & Senior Counsel

As required by the Securities Act of 1933, this Registration Statement has been signed below by the following persons in the capacities with the Depositor, Sun Life Assurance Company of Canada (U.S.), and on the dates indicated.

SIGNATURE	TITLE	DATE
/s/ Robert C. Salipante*	President and Director	November 17, 2006
Robert C. Salipante	(Principal Executive Officer)
/s/ Ronald H. Friesen	Vice President, Chief Financial Officer and	November 17, 2006
Ronald H. Friesen	Treasurer and Director
	(Principal Financial Officer)
/s/ Michael K. Moran	Vice President, Chief Accounting Officer and Controller	November 17, 2006
Michael K. Moran	(Principal Accounting Officer)
*By: /s/ Sandra M. DaDalt	Attorney-in-Fact for:	November 17, 2006
Sandra M. DaDalt	Donald A. Stewart, Director
	Thomas A. Bogart, Director
	Scott M. Davis, Director and Vice President and General            Counsel
	Mary M. Fay, Director and Vice President and General            Manager, Annuities

*Sandra M. DaDalt has signed this document on the indicated date on behalf of the above Directors for the Depositor pursuant to powers or attorney duly executed by such persons and a resolution of the Board of Directors authorizing use of powers of attorney for Officer signatures. Resolution of Board of Directors is incorporated herein by reference to the Registration Statement of Keyport Variable Account A on Form N-4, File No. 333-112506, filed on or about February 5, 2004. Powers of attorney are incorporated herein by reference to Post-Effective Amendment No. 13 to the Registration Statement on Form N-4, File No. 333-83516, filed on February 3, 2006.