Forty-four elderly patients (mean age, 77.2 years; range, 65 to 95) with acute bile duct obstruction, with gallbladder in situ, underwent endoscopic sphincterotomy without subsequent cholecystectomy during the same hospitalization. Thirty patients had periampullary duodenal diverticula, and 14 had no diverticula. Because periampullary diverticula were associated with biliary and pancreatic complications, possibly as a result of stasis in the diverticula, the clinical course in patients with and without diverticula was compared. Endoscopic sphincterotomy was well tolerated and resulted in a rapid clinical improvement in all patients. There were four complications related to the procedure (pancreatitis, two, and cholangitis, two), all were treated conservatively, and there were no deaths. The clinical outcome was similar in both groups of patients. During a mean follow-up of 25 months (range, 6 to 58), only two patients (one of each group) underwent elective cholecystectomy 2 and 3 months after initial presentation. It is concluded that endoscopic sphincterotomy is a safe and effective alternative to surgery as an initial treatment in elderly patients with choledocholithiasis and gallbladder in situ. Periampullary duodenal diverticulum does not interfere with the favorable results of endoscopic sphincterotomy in patients with gallbladder in situ.