The sphincter of Oddi occupies a key position anatomicaly. Situated as it is at the terminus of the main pancreatic and common bile ducts, it regulates the flow of pancreatic juice and bile into the duodenum in response to a wide variety of stimuli. This important sphincter is subject to many influences, mechanical, chemical, pharmacological, hormonal, and nervous. Its role in the etiology of acute and recurrent pancreatitis has been repeatedly stressed in the literature of the past 30 years, with recent reemphasis on section of the sphincter as an operative maneuver of therapeutic value.* The etiologic relationship of the sphincter of Oddi to biliary dyskinesia, cholecystitis, and the postcholecystectomy syndrome is also mentioned, and, in the recent literature, section of the sphincter of Oddi has been recommended in the last-named condition.† It is the intent of this review to stress in addition the possible critical role of the sphincter