THE CORPORATE LIBRARY

Related Party Transactions and Outside Related Director Information

Lexicon Genetics Incorporated (LEXG)

3/24/2006 Proxy Information

We are party to a consulting agreement with C. Thomas Caskey, M.D. dated March 28, 2005, under which Dr. Caskey serves as a consultant to us on governmental affairs and other matters. Dr. Caskey receives payment of $75,000 per year for his consulting services under the agreement. The agreement expires on March 28, 2006.

We are party to a consulting agreement with Robert J. Lefkowitz, M.D. dated March 31, 2003, under which Dr. Lefkowitz serves as a consultant to us on matters relating to our drug discovery and development efforts. Dr. Lefkowitz receives payment of $50,000 per year for his consulting services under the agreement. The agreement has an initial term of one year and is automatically extended for additional one-year terms unless otherwise terminated by the parties.

We are party to a consulting agreement with Alan S. Nies, M.D. dated February 19, 2003, as amended, under which Dr. Nies serves as chairman of our Medical Advisory Board and provides consulting services on matters relating to our drug discovery and development efforts. Dr. Nies receives payment of $75,000 per year for his consulting services under the agreement and received an option under our 2000 Equity Incentive Plan to purchase 2,500 shares of common stock at an exercise price of $4.06 per share, the fair market value of our common stock on the date of grant as determined in accordance with the plan. The agreement has an initial term of one year and is automatically extended for additional one-year terms unless otherwise terminated by the parties.

3/28/2005 Proxy Information

Dr. Lefkowitz has been a consultant to Lexicon Genetics Incorporated since March 2003.