Drug Discovery is an emerging pharmacological science that seeks to identify novel small molecule probes and to understand at a molecular level how compounds affect macromolecular process. Cell-based, in vitro mix-and-read, and whole organism assays suitable for rapid or high throughput analysis are being designed and implemented by members of the Molecular Pharmacology Program. Current molecular targets include Gprotein coupled receptors, vanilloid receptors, cathepsins, apoptosis-inducing proteins, ion channels, steroid receptors, orphan nuclear receptors, kinases, phosphatases, DNA repair enzymes, and DNA polymerases. Chemical libraries and automated screening instrumentation are emphasized, which permit rapid interrogation of optimized assays. Computational approaches and high content cell screening methodologies are employed to facilitate the identification of new chemical probes.