A commercially available robot system, the Zymark Zymate Laboratory Automation System, has been utilized for the preparation of a positron-emitting radiopharmaceutical, 16 alpha-[18F] fluoroestradiol-17 beta. This radiopharmaceutical is prepared in a three-step synthesis (preparation of [18F]-tetrabutylammonium fluoride, SN2 displacement of a triflate, and ketone reduction) and is purified by high performance liquid chromatography (HPLC). All steps in the synthesis and HPLC purification are controlled by the robot system with no manual intervention. This represents a new approach to the complete automation of radiopharmaceutical production.