Exhibit 1


                         XOMA CONTACTS: Ellen M. Martin
                         510-644-1170 or 800-BIO XOMA
                         Thomson IR: Juliane Snowden
                         212-510-9286 or Tariq Jawad
                         212-510-9346 for a copy of
                         recent releases call: Fax
                         News on Demand 1-800-901-7788
                         or visit XOMA @ www.xoma.com


XOMA ANNOUNCES $17.4 MILLION COMMON SHARE FINANCING

Berkeley, CA - July 22, 1999 - XOMA Ltd. (Nasdaq: XOMA) today announced it has
sold 3.0 million common shares in a private financing for gross proceeds of
$17.4 million. Sutro & Company and Arnhold & S. Bleichroeder served as placement
agents for this transaction.

"Our policy has been to maintain a cash level that will fund our operations for
roughly one year," said Peter B. Davis, XOMA's Chief Financial Officer. "Our
June 30 cash balance was approximately $20 million. This financing brings us to
a more appropriate level in advance of unblinding the data from our recently
completed Phase III trial testing NEUPREX(R) in meningococcemia patients. We are
very pleased to complete a straight common share transaction, with no future
price adjustments or additional warrants issued to the investors."

Financing proceeds will be used primarily to fund continued development of
products from XOMA's BPI (bactericidal/permeability-increasing protein) drug
development platform. Besides the recently completed Phase III trial in
meningococcemia patients, the Company's lead BPI-derived product, NEUPREX(R), is
also being tested in a Phase III trial in patients suffering from hemorrhage due
to trauma. XOMA is currently reviewing additional potential indications for
NEUPREX(R). Other BPI-derived compounds are in earlier stages of development.

In addition to its BPI platform, XOMA is collaborating with Genentech on the
hu1124 (anti-CD11a) humanized monoclonal antibody product. The two companies
anticipate starting Phase III trials in patients with moderate to severe
psoriasis later this year.

     XOMA Ltd. develops and manufactures biopharmaceuticals at facilities
located in Berkeley and Santa Monica, California. The Company's medical targets
include bacterial and fungal infections, infectious complications (such as those
that may follow trauma or surgery), immunologic and inflammatory disorders.
XOMA's primary drug development plat-





form is the BPI molecule, a human protein with multiple anti-infective
properties that is part of the body's defense system against microbial
infection.


Statements made in this press release related to the timing of clinical trials,
release of data and other aspects of product development, or that otherwise
relate to future periods, are forward-looking statements within the meaning of
Section 27A of the Securities Act of 1933 and Section 21E of the Securities
Exchange Act of 1934. These statements are based on assumptions which may not
prove accurate. Actual results could differ materially from those anticipated
due to certain risks inherent in the biotechnology industry and for companies
engaged in the development of new products in a regulated market. These risks,
including those related to the timing or results of pending or future clinical
trials, changes in the status of the Company's collaborative relationships,
uncertainties regarding the legal standards applicable to biotechnology patents,
and actions by the U.S. Food and Drug Administration or the U.S. Patent and
Trademark Office, are discussed in the Company's most recent annual report on
Form 10-K and in other SEC filings. Consider such risks carefully in evaluating
XOMA's prospects.

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