EXHIBIT 99.1

                  LA JOLLA PHARMACEUTICAL COMPANY TO PRESENT AT
                      UBS WARBURG LIFE SCIENCES CONFERENCE

SAN DIEGO, SEPTEMBER 22, 2003 -- La Jolla Pharmaceutical Company (Nasdaq: LJPC)
announced today that its Chairman and Chief Executive Officer, Steven B. Engle,
will present at the annual UBS Warburg Global Life Sciences Conference at The
Plaza Hotel in New York City. Mr. Engle will present on Wednesday, September 24,
2003 at 11:30 a.m. eastern time. Those wishing to access the audio portion of
the presentation may link to the UBS homepage at http://www.ibb.ubs.com and
click on the "Conferences" button in the middle of the page. Follow the link for
Webcast under the Global Life Sciences Conference heading.

La Jolla Pharmaceutical Company is a biotechnology company developing
therapeutics for antibody-mediated autoimmune diseases afflicting several
million people in the United States and Europe. The Company is developing
Riquent(TM), formerly known as LJP 394, for the treatment of lupus kidney
disease, a leading cause of sickness and death in patients with lupus. The
Company is also developing LJP 1082 for the treatment of antibody-mediated
thrombosis, a condition in which patients suffer from recurrent stroke,
deep-vein thrombosis and other thrombotic events. The Company's common stock is
traded on The Nasdaq Stock Market under the symbol LJPC. For more information
about the Company, visit its Web site: http://www.ljpc.com.

Except for historical statements, this press release contains, and Mr. Engle's
presentation will contain forward-looking statements involving significant risks
and uncertainties, and a number of factors, both foreseen and unforeseen, could
cause actual results to differ materially from our current expectations.
Forward-looking statements include those which express a plan, belief,
expectation, estimation, anticipation, intent, contingency, future development
or similar expression. Although we plan to submit a New Drug Application ("NDA")
for Riquent(TM), there is no guarantee that regulatory authorities will approve
Riquent in a timely manner, or at all. Our analyses of clinical results of
Riquent, previously known as LJP 394, our drug candidate for the treatment of
systemic lupus erythematosus ("lupus"), and LJP 1082, our drug candidate for the
treatment of antibody-mediated thrombosis ("thrombosis"), are ongoing and could
result in a finding that these drug candidates are not effective in large
patient populations, do not provide a meaningful clinical benefit, or may reveal
a potential safety issue requiring us to develop new candidates. The analysis of
the data from our Phase 3 trial of Riquent has shown that the trial did not
reach statistical significance with respect to its primary endpoint, time to
renal flare. Although we plan to submit an NDA for Riquent, the results from our
clinical trials of Riquent may not ultimately be sufficient to obtain regulatory
clearance to market Riquent either in the U.S. or Europe, and we may be required
to conduct additional clinical studies to demonstrate the safety and efficacy of
Riquent to obtain marketing approval. There is no guarantee, however, that we
will have the necessary resources to complete any additional trial, that we will
elect to conduct an additional trial, or that any additional trial will
sufficiently demonstrate the safety and efficacy of Riquent. Our blood test to
measure the binding affinity for Riquent is experimental, has not been validated
by independent laboratories, may require regulatory approval, and will likely be
necessary for the approval and the

commercialization of Riquent. Our other potential drug candidates are at earlier
stages of development and involve comparable risks. Analysis of our clinical
trials could have negative or inconclusive results. Any positive results
observed to date may not be indicative of future results. In any event,
regulatory authorities may require additional clinical trials, or may not
approve our drugs. Our ability to develop and sell our products in the future
may be affected by the intellectual property rights of third parties. Additional
risk factors include the uncertainty and timing of: obtaining required
regulatory approvals, including delays associated with any approvals that we may
obtain; the clear need for additional financing; FDA approval of our
manufacturing facilities and processes; the increase in capacity of our
manufacturing capabilities for possible commercialization; successfully
marketing and selling our products; our lack of manufacturing, marketing, and
sales experience; generating future revenue from product sales or other sources
such as collaborative relationships; future profitability; and our dependence on
patents and other proprietary rights. Readers are cautioned to not place undue
reliance upon forward-looking statements, which speak only as of the date
hereof, and we undertake no obligation to update forward-looking statements to
reflect events or circumstances occurring after the date hereof. Interested
parties are urged to review the risks described in our Annual Report on Form
10-K for the year ended December 31, 2002, and in other reports and registration
statements that we file with the Securities and Exchange Commission from time to
time.

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