Exhibit 10.29

[Company Letterhead]

October 15, 2007

Gail Schulze

[Home address omitted]

Dear Gail:

Cerus is very pleased to offer you a seat on our Board of Directors. Subject to
your acceptance of this offer, your nomination as a Board member will be
presented to the Board for approval at the next regular Cerus Board Meeting,
scheduled for October 25, 2007 at 8:30am. at our Concord headquarters.

As a new member of the Cerus Board of Directors, you will receive an option for
25,000 shares on the first business day of the next month following the opening
of our insider trading window. The option will vest on a monthly basis over a
period of four years, with vesting commencing on October 25, 2007 (your first
day as a director). In addition, there will be an automatic grant of an
additional option of 2,794 shares on January 1, 2008, representing a pro rata
portion (68 days) of the outside directors’ annual 15,000 share refresh of
options. Since your 25,000 share grant is intended in part to cover the first 12
months of your service, you will receive this option for 2,794 shares in lieu of
the regular 15,000 share option that the other outside directors will receive
for 2008. This option will vest monthly over 2008, with full vesting on December
31 of that year.

Additionally, you will receive an annual cash retainer of $20,000 (pro-rated for
2007) paid on a quarterly basis and Board Meeting fees of $2,000 ($1,000 for
telephonic meetings). Cerus will also reimburse your travel related expenses
(per the Cerus travel policy) incurred as a result of your Board Meeting
attendance.

Please kindly confirm your acceptance of our board position and your
understanding of our option compensation by signing and returning a copy of this
letter to me. A fax copy will be fine. Please feel free to call if you have any
questions.

Very truly yours,

/s/ Claes Glassell

Claes Glassell

President and C.E.O.

 

cc: Lori Roll

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

CONFIRMED AS SET FORTH ABOVE

/s/ Gail Schulze

Gail Schulze