The Woodlands, Texas, September 14, 2005 – Arthur T. Sands, M.D., Ph.D., president, chief executive officer and co-founder of Lexicon Genetics Incorporated (Nasdaq: LEXG), will ring The NASDAQ Stock Market Opening Bell on Wednesday, September 21, 2005 to celebrate the tenth anniversary of the company’s founding.  Lexicon Genetics began trading on NASDAQ in April of 2000.

Details of the opening bell ceremony appear below:

Where: NASDAQ MarketSite – 4 Times Square at 43rd and Broadway

When: Wednesday, September 21, 2005 at 9:30 a.m., EDT

Web Cam:
To view the Opening Bell, visit http://www.nasdaq.com/reference/marketsite_about.stm and follow the instructions below:
- Scroll to the bottom of the page under the heading MarketSite Live Web cam and click on Windows Media Player
- Viewers should download the web cam at 9:15 a.m. in order to have time to trouble shoot in case of technical difficulties
- Before 9:20 a.m., the web cam will show the Tower.  At 9:20 a.m., the router is switched to show the studio

Broadcast Feed:
The opening bell is available from 9:20 a.m. to 9:35 a.m. on uplink IA-5 C-band/transponder 14.  The downlink frequency is 3980 horizontal; audio: 6.2/6.8.  The feed can also be found on Waterfront fiber 1623.  If you have any questions, contact NASDAQ’s Stephanie Lowenthal at (646) 441-5220.

Photos: To obtain a hi-resolution photograph of the Market Open, visit www.nasdaq.com/reference/marketsite_events.stm.
 

About Lexicon Genetics

Lexicon Genetics is a biopharmaceutical company focused on the discovery and development of breakthrough treatments for human disease.  Lexicon is systematically discovering the physiological and behavioral functions of genes to identify potential points of therapeutic intervention, or drug targets.  Lexicon makes these discoveries using its proprietary gene knockout technology to model the physiological effects that could be expected from prospective drugs directed against novel targets.  The Company has advanced knockout-validated targets into drug discovery programs in six therapeutic areas:  diabetes and obesity, cardiovascular disease, psychiatric and neurological disorders, cancer, immune system disorders and ophthalmic disease.  Lexicon is working both independently and through strategic collaborations and alliances to accelerate the development and commercialization of its discoveries.  Additional information about Lexicon is available through its corporate website, www.lexicon-genetics.com.

Safe Harbor Statement

This press release contains “forward-looking statements,” including statements about Lexicon’s growth and future operating results, discovery and development of products, strategic alliances and intellectual property, as well as other matters that are not historical facts or information.  These forward-looking statements are based on management’s current assumptions and expectations and involve risks, uncertainties and other important factors, specifically including those relating to Lexicon’s ability to successfully conduct preclinical development of its drug candidates and advance such candidates into clinical development, achieve its operational objectives, obtain patent protection for its discoveries and establish strategic alliances, as well as those relating to manufacturing, the regulatory process, intellectual property rights, and the therapeutic or commercial value of its drug candidates, that may cause Lexicon’s actual results to be materially different from any future results expressed or implied by such forward-looking statements. Information identifying such important factors is contained under “Factors Affecting Forward-Looking Statements” and “Business – Risk Factors” in Lexicon’s annual report on Form 10-K for the year ended December 31, 2004, as filed with the Securities and Exchange Commission.  Lexicon undertakes no obligation to update or revise any such forward-looking statements, whether as a result of new information, future events or otherwise.