Drug discovery around the world changed dramatically in the 1990s.High-throughput screening matured during this decade so that pharma and biotech companies could screen tens of thousands of compounds per day from their libraries.Perhaps more importantly, however, regulatory agencies became more and more involved in the safety of new medicines, especially toward the end of the decade.In the late 90s several medicines were removed by the FDA in the US because of deaths caused by arrhythmias.As a result, the FDA posted new guidelines for drug safety and strongly recommended that all drugs expecting approval be tested using the patch clamp technique against hERG potassium channels.The patch clamp method involves measuring small (~10-10 amps) of electrical current in single living cells.hERG potassium channels regulate repolarization of action potentials in heart muscle cells.At the time of these FDA regulations, however, patch clamp required a highly specialized scientist and happened very slowly...one cell at a time.Several companies around the world met the challenge by developing higher throughput and automated patch clamp machines.The first systems hit the market in 2002.This presentation will describe the historical background for automated patch clamp and discuss the present and future role in drug discovery and safety pharmacology.