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

[DRAFT dated April 11, 2006]

Securities and Exchange Commission

Judiciary Plaza

450 Fifth Street, N.W.

Washington, D.C. 20549

Re:	Sun Life of Canada (U.S.) Variable Account F ("Registrant")
	Sun Life Assurance Company of Canada (U.S.) ("Depositor")
	Post-Effective Amendment No. 16 to the Registration Statement
	on Form N-4 ("Registration Statement")
	File Nos. 811-05846 and 333-83516

Commissioners:

Registrant suggests revising its transmittal letter to the SEC regarding File No. 333-83516 by replacing the responses to Questions 5, 6, and 7 as follows:

5.	OPTIONAL LIVING BENEFIT RIDER: SECURED RETURNS FOR LIFE PLUS - Plus 5 Program
		The Staff noted that the disclosure describing the "Plus 5 Program" was confusing and did not adequately describe how an Owner could maximize his/her benefits under the Program.
		Response: The Registrant has rewritten this section by first describing in general terms the additional benefit provided by the Program and then describing how the Program operates differently under each of the two Plans (the AB Plan and the WB Plan). [See ATTACHMENT 1-A.]

6.	OPTIONAL LIVING BENEFIT RIDER: SECURED RETURNS FOR LIFE PLUS - Withdrawals Under the Optional Living Benefit Rider
a.		The Staff asked the Registrant to clarify the disclosure under "Withdrawals Under the Optional Living Benefit Rider." Specifically, the Staff suggested an explanation of the relationship between the calculations and the value of the Owner's benefit when withdrawals are taken.
		Response: The Registrant has extensively rewritten the disclosure under this section by first describing in general terms the affect of withdrawals under the Secured Returns for Life Plus and then describing how withdrawals operate differently under each of the two Plans (the AB Plan and the WB Plan). [SEE ATTACHMENT 2.]

7.	OPTIONAL LIVING BENEFIT RIDER: SECURED RETURNS FOR LIFE PLUS - Tax Issues
		The Staff the ask Registrant to clarify the disclosure contained in the third paragraph under "Tax Issues" so that an Owner can understand what happens to his/her benefit when RMD withdrawals are taken.
		Response: The Registrant has rewritten the second, third, and fourth paragraphs under "Tax Issues" to clarify (1) how required withdrawals under current Federal tax laws operate under the Secured Returns for Life Plus and (2) how we ensure that the contract owners will not be penalized for complying with the Federal tax laws.

In addition to these responses, Registrant is providing a chart of acronyms to assist in reading the disclosure under "OPTIONAL LIVING BENEFIT RIDER: SECURED RETURNS FOR LIFE PLUS." (See ATTACHMENT 5.")

* * * * * *

Please direct all questions and comments to the undersigned at (781) 263-6402 or to Thomas C. Lauerman, Esquire, of Jorden Burt LLP at (202) 965-8100.

Respectfully yours,

/s/ Sandra M. DaDalt

Sandra M. DaDalt

Assistant Vice President & Senior Counsel

cc:	Thomas C. Lauerman, Esquire
	Rebecca Marquigny, Esquire

ATTACHMENT 1-A

Plus 5 Program

The Plus 5 Program gives you the opportunity to increase your guaranteed living benefit if you defer taking withdrawals. That is to say, if you have selected the Benefit and you do not take any withdrawals in the early Account Years, you will be able to take larger withdrawals in the later Account Years. Under Secured Returns for Life Plus, the Plus 5 Program is automatically available to you during your first 10 Account Years (the "Plus 5 Period"). However, if you are 70 or older on the Issue Date, the Plus 5 Period ends on your 80th birthday. Under the Plus 5 Program, if you do not take any withdrawals during any one or more Account Years, we will automatically calculate a bonus based upon your initial Purchase Payment (the "Bonus Base") and adjusted for additional Purchase Payments, step-ups, and partial withdrawals. Although we calculate the amount of your bonus each year regardless of whether you are participating in the AB Plan or the WB Plan, you can benefit from any bonus amount only if you choose to participate in the WB Plan, as follows:

l	Assume you are participating in the AB Plan. Under this Plan, you only have the potential for increasing the amount of your withdrawals in later Account Years. For each year you do not take a withdrawal during the Plus 5 Period, we will calculate a bonus equal to 5% of your Bonus Base and add it to an existing accrued bonus amount. The bonuses you earn will accumulate but will not increase your Account Value, your GLB amount, or any guarantee payments you receive under the AB Plan. If you choose to switch to the WB Plan, that potential for larger withdrawals will be realized. When you switch to the WB Plan, we will set your RGLB amount to equal your GLB amount plus any bonuses accumulated under your Contract while you were participating in the AB Plan.
l	Assume you are participating in the WB Plan. Under this Plan, the potential for larger withdrawals will be realized. Each year you do not take a withdrawal during the Plus 5 Period, we will not only calculate a bonus equal to 5% of your Bonus Base, but we will add that bonus to your RGLB amount on your Account Anniversary. In this way, your withdrawals under the WB Plan will be larger in the later years than they would have been without the Plus 5 Program. Each time we add a bonus to the RGLB amount, we will also recalculate your GLB Base and Lifetime Income Base as described below.
	After the addition of any bonus, your new GLB Base will be the greater of:
l		your GLB Base prior to the addition of the amount of any bonus, and
l		your RGLB amount after the addition of any applicable bonus.
	If your age is within our age limitations, we will calculate a new Lifetime Income Base. Your new Lifetime Income Base will be equal to the greater of:
l			your Lifetime Income Base prior to the addition of the bonus amount, and
l			the lesser of:
l		your RGLB amount after the addition of the bonus amount, and
l		your previous Lifetime Income Base plus the addition of any bonus amount.

ATTACHMENT 2

Withdrawals Under the Optional Living Benefit Rider

All withdrawals under Secured Returns for Life Plus are subject to withdrawal charges if they are in excess of the annual free withdrawal amount. (See "Free Withdrawal Amount" under "Withdrawal Charge.") In addition, any withdrawals you take under Secured Returns for Life Plus will reduce the value of your benefit under the rider. Such withdrawals affect your benefit differently depending upon whether you are participating in the AB Plan or the WB Plan.

Assume you are participating in the AB Plan. Any withdrawals you make will reduce the dollar value of your benefits under this rider proportionally to the amount withdrawn. For example, after a partial withdrawal, the new GLB amount will equal

old GLB amount x	Account Value immediately before partial withdrawal
	Account Value immediately after partial withdrawal

Therefore, on your AB Maturity Date, instead of crediting your Account Value with the full amount of your benefit, we will reduce the amount we credit proportionally to the amount withdrawn. We will also proportionally reduce your Bonus Base and any accrued bonuses using a similar calculation. (See Examples 3 and 15 in Appendix I.) However, as discussed in detail under "Plus 5 Program," even though the Bonus Base and accrued bonuses are calculated while you are in the AB Plan, you can benefit from any bonus amount only if you choose to participate in the WB Plan.

Assume you are participating in the WB Plan and you want to receive the full amount of your guaranteed benefit over a period of years. To maximize your guaranteed benefit, you may withdraw no more than a specified amount each year. In other words, each year, you may withdraw no more than your Maximum WB Amount. Your guaranteed benefit amount (the RGLB amount) will be reduced dollar for dollar, but your Maximum WB Amount will remain unchanged. In other words, you will be able to take the same maximum amount each year until your guaranteed benefit amount is completely withdrawn.

If, however, in any one Account Year, you withdraw more than the current Maximum WB Amount, the dollar value of your guaranteed benefits will be reduced and the amount of each future annual guaranteed withdrawal will be less. Here is how we calculate the benefit reduction. Your new RGLB amount will be the lesser of:

l	your previous RGLB amount, reduced dollar for dollar by the amount of the withdrawal and
l	your Account Value after the withdrawal.

Your new GLB will be the lesser of:

l	your previous GLB Base reduced dollar for dollar by the amount of the excess withdrawal, and
l	your Account Value after the withdrawal.

Your new Bonus Base will be the lesser of:

l	your previous Bonus Base reduced dollar for dollar by the amount of the excess withdrawal, and
l	your Account Value after the withdrawal.

Your new Maximum WB Amount will be 5% of you new reduced GLB Base. Going forward, this will be the maximum amount that you can withdraw annually without further reducing your benefit.

The Maximum WB Amount is not cumulative. If you withdraw less than the Maximum WB Amount in any one Account Year, you cannot add that unused portion to withdrawals made in future years to increase the Maximum WB Amount.

Assume you are participating in the WB Plan and, instead, you want to receive a guaranteed annual amount for the rest of your life. To maximize your guaranteed benefit, you may withdraw no more than a specified amount each year. Under this scenario, you may withdraw no more than your Maximum WB for Life Amount. Your guaranteed benefit amount (the RGLB amount) will be reduced dollar for dollar, but your Maximum WB for Life Amount will remain unchanged. In other words, you will be able to take the same maximum amount each year as long as you are alive.

If, however, in any one Account Year, you withdraw more than the current Maximum WB for Life Amount, the dollar value of your guaranteed benefits will be reduced and the amount of each future annual guaranteed withdrawal will be less. Here is how we calculate the benefit reduction. Your new Lifetime Income Base will be the lesser of

l	your previous Lifetime Income Base reduced dollar for dollar by the amount of the excess withdrawal, and
l	the Account Value after the withdrawal.

A new Maximum WB for Life Amount will be determined based upon your age on the date of the first withdrawal under the WB Plan (or your age on the last "Step-Up Date," if later) as follows:

Your Age on the later of Date of First Withdrawal under WB Plan or Last Step-Up Date	New Maximum WB for Life Amount
65 or older	5% of the new Lifetime Income Base
64 or younger	4% of the new Lifetime Income Base

The Maximum WB for Life Amount is not cumulative. That is to say, the unused portion in any Account Year cannot be applied in future years to increase the Maximum WB for Life Amount.

In general when participating in the WB Plan, you should keep the following in mind:

l	A withdrawal in excess of the Maximum WB Amount or the Maximum WB for Life Amount might reduce or eliminate your Secured Returns for Life Plus Benefits
l	If your Account Value drops to zero and, in the same year, you withdraw more than your Maximum WB Amount or your Maximum WB for Life Amount, your benefits under Secured Returns for Life will terminate.
l	If your Account Value drops to zero but you did not, in the same year, withdraw more than your Maximum WB Amount or your Maximum WB for Life Amount, your benefits under Secured Returns for Life will continue. However, no subsequent Purchase Payment will be accepted, no death benefit or annuity benefits will be payable, and all benefits under your Contract, except the right to continue annual withdrawals under this rider, will terminate. You will have two choices:
(1)		You could choose to receive the Maximum WB for Life Amount, if any, until an Owner dies. After the death of an Owner, your beneficiary receives the Maximum WB Amount until the RGLB amount, if any, is reduced to zero; or
(2)		You (or your beneficiary if an Owner has died) could choose to receive the Maximum WB Amount until the RGLB amount, if any, is reduced to zero
	If you do not make a choice, we will default you to option 1.

For examples showing how withdrawals affect your benefits under the WB Plan, see Examples 7 and 12 in Appendix I.

ATTACHMENT 2-A

If your Contract is a Qualified Contract, the retirement plan governing that Qualified Contact may be subject to certain required minimum distribution ("RMD") provisions imposed by the Internal Revenue Code (the "Code") and IRS regulations (collectively, the "Federal Tax Laws"). These RMD provisions require that a yearly amount be distributed from the retirement plan beginning generally in the calendar year you attain age 70 1/2. Your failure to withdraw your yearly RMD amount from your Qualified Contract ("Yearly RMD Amount") could result in adverse tax treatment.

In the event that your Yearly RMD Amount attributable to your Contract is greater than the maximum withdrawal amount permitted each year under the WB Plan, we are currently waiving withdrawal provisions under Secured Returns for Life Plus as follows.if you withdraw all or a portion of your Qualified Contract's Yearly RMD Amount from the Contract while participating in the WB Plan, we reduce your Account Value and your RGLB amount, dollar for dollar, by the amount of the withdrawal. We will not, however, penalize you if the current Federal Tax Laws require you to withdraw from your Contract an amount greater than either your Maximum WB Amount, or your Maximum WB for Life Amount. In other words, we will not reduce your GLB Base, Lifetime Income Base, or Bonus Base, if a Yearly RMD Amount exceeds either your Maximum WB Amount or your Maximum WB for Life Amount, provided that

(1)	you withdraw your Qualified Contract's first Yearly RMD Amount in the calendar year you attain age 70 1/2 rather than postponing the withdrawal of that Amount until the first quarter of the next calendar year, and
(2)	you do not make any withdrawal from your Qualified Contract that would result in you receiving, in any Account Year, more than one calendar year's Yearly RMD Amount.

When you elect to participate in the WB Plan, we will inform you that you may withdraw annual amounts up to your Yearly RMD Amount without reducing your guaranteed withdrawal benefit. To assist you in complying with the RMD requirements, each year, we will notify you in early January of your calculated Yearly RMD Amount and inform you that you may withdraw annual amounts up to your Yearly RMD Amount without reducing your guaranteed withdrawal benefit.

If there is any change to the current Code or IRS rules governing the timing or determination of RMD amounts (including, but not limited to, amendments to the current IRS regulations or the issuance of IRS guidance), then we reserve the right to reduce GLB Base, Lifetime Income Base, Bonus Base, or all of these amounts, per the terms of the Contract regarding excess withdrawals (see "Withdrawals Under the Optional Living Benefit Rider"), when a Yearly RMD Amount withdrawn from your Contract exceeds either your Maximum WB Amount or your Maximum WB for Life Amount.

ATTACHMENT 5

To assist you in reading and understanding Secured Returns for Life Plus, Registrant is providing the following of chart of acronyms:

WB Plan	Guaranteed Minimum Withdrawal Benefit Plan
AB Plan	Guaranteed Minimum Accumulation Benefit Plan
GLB Amount	Guaranteed Living Benefit Amount
RGLB Amount	Remaining Guaranteed Living Benefit Amount
Maximum WB Amount	Maximum Guaranteed Minimum Withdrawal Benefit Amount
Maximum WB for Life Amount	Maximum Guaranteed Minimum Withdrawal Benefit for Life Amount
RMD Amount	Required Minimum Distribution Amount
Yearly RMD Amount	Yearly Required Minimum Distribution Amount