Genetic programming \citekoza:book \citebanzhaf:1997:book \citelangdon:fogp is an established artificial intelligence technique which is used in many areas. Essentially it applies the older genetic algorithm technique \citeholland:book \citegoldberg:book to automatically generate programs. (See Figure 1.) The next section will introduce genetic programming, including a very short over view of the many areas where GP has been applied, before Section 4 concentrates on uses of genetic programming in the Pharmaceutical industry. We finish with a worked example (Section 5) which describes an evaluation of machine learning for predicting potential drugs’ activity with an pharmaceutically important enzyme (Human cytochrome P450 2D6) made by GlaxoSmithKline chemists \citelangdon:2001:wsc6, \citelangdon:2002:EuroGP, \citelangdon:2002:kdmdd, \citelangdon:2002:iberamia, \citehis02Plenary:Langdon, \citelangdon:2003:CEC. Appendix A gives pointers to further information.