Pressures in the sphincter of Oddi and common bile duct were determined in eight patients with previous surgical sphincterotomy, and in 14 patients before and after endoscopic sphincterotomy. Motor activity in the sphincter of Oddi was seen during manometric examination in 6 out of 8 patients of the surgical group. These six patients had common bile duct stones after cholecystectomy. Endoscopic sphincterotomy equalized the choledochoduodenal gradient and reduced the sphincter pressure in all the patients except three. In two of them further extension of the length of the sphincterotomy permitted removal of the stones and substantial reduction of the motor activity of the sphincter of Oddi.