SecProbe.io

July 1 , 2013

Via E -mail
Fred Kurland
Chief Financial Officer
XOMA Corporation
2910 Seventh Street
Berkeley, CA 94710

Re: XOMA Corporation
Form 10 -K for the Fiscal year Ended December  31, 2012
Filed March 12 , 2013
File No. 000 -14710

Dear Mr. Kurland :

We have reviewed your filing and have the following comment s. In our comment s, we
may ask you to provide us with infor mation so we may better understand your disclosure.

Please respond to this letter within 10 business days by providing the requested
infor mation or by advising us when you will provide the requested response .  If you do  not
believe our comment s apply  to your facts and circu mstances , please tell us why in your
response.

After revie wing the infor mation you provide  in response to these  comments, we may
have additio nal co mments.

Technologies and Technology Licenses, page 6

1. In this section you identify three trademarked core technologies, ADAPT, ModulX , and
OptimX, which are owned by you and available for licensing to other companies.   We
also note the disclosure on page 28 which indicates that you have licensed some of your
technology from other parties.   If these technologies have been key to the developme nt of
your product pipeline and you have licensed any of these core technologies from third
parties , please identify the third parties, file all material licensing agreements , and
describe the material terms of these agreements.   Alternatively, if you beli eve that the
development of your product pipeline is not substantially dependent upon maintaining
any or all of these agreements , please provide us a substantive analysis supporting your
conclusions.

Fred Kurland
XOMA Corporation
July 1 , 2013
Page 2

 Patents and Trade Secrets, pages 18 -19

2. In the secon d paragraph you identify ten different patents that relate to your gevokizumab
product.  We note that two of these patents relate to the Type 2 diabetes program, one
relates to the osteoarthritis program, one relates to the cancer program , and another
relates to the coronary program.   You do not specify to which gevokizumab programs the
five other patents apply. You should disclose to which programs these five other patents
apply.  If these apply to the use of gevokizumab generally you should clarify.  In any
case, you should identify the patents that  apply to the treatment of NIU and Behcet’s
uveitis , as these indications are the most advanced.  Please also separately disclose the
year of expiration of  each of the ten patents you identify as being related to gevokizumab
and the nature of the patent or type of patent protection applying to each . Additionally ,
please clarify as to each of the patents related to gevokizumab whether they were in -
licensed from Les Laboratoires Servier or some other third party , or developed in -house
and filed with the P atent and Trademark Office by the registrant.

We urge all persons who are responsible for the accuracy and adequacy of the disclosure
in the filing to be certain that the filing includes all information the Securities Exchange Act of
1934 and all applicable Exchange Act rules require .  Since the company and its management are
in possession of all facts relating to a company’s disclosure, they are responsible for the accuracy
and adequacy of the disclosures they have made.

In responding to our comments, please provide a written statement from the company
acknowledging that :

 the company is responsible for the adequacy and accuracy of the disclosure in the filing ;

 staff comments or changes to disclosure in response to staff comments do not fore close
the Commission from taking any action with respect to the filing ; and

 the company may not assert staff comment s as a defense in any proceeding initiated by
the Commission or any person under the federal securities laws of the United States .

Please  contact Austin Stephenson at (202) 551 -3192 or me at (202) 551 -3715 with any
questions.

Sincerely,

 /s/ Jeffrey P. Riedler

 Jeffrey P. Riedler
Assistant Director