Summary Endoscopic sphincterotomy (ES) is a simple, effective and remarkably safe method of treatment of choledocholithiasis and papillary stenosis. In this series, ES was technically successful in 255 (86·1 per cent) of 296 patients in whom it was attempted. Forty-nine of the successful cases had papillary stenosis complicated by pain, cholangitis and/or jaundice in patients after cholecystectomy; 205 had choledocholithiasis, of whom 164 had a cholecystectomy and 41 were poor surgical risks and did not have cholecystectomy. One patient had a tumour of the ampulla of Vater. ES has been performed as an emergency in 16 subjects because of severe septic cholangitis in 11 and acute biliary pancreatitis in 5. Of the 205 patients with choledocholithiasis, spontaneous passage of calculi after ES occurred in 151 cases (73·6 per cent), and instrumental extraction of stones was possible in 44 (21·5 per cent); 10 patients (4·9 per cent) had residual stones and required surgery. In this series the overall success rate of ES in removing common bile duct stones was 82 per cent in 238 cases; in the patients with benign papillary stenosis ES was successful in relieving symptoms and biochemical cholestasis in 72 per cent of 57 cases. Complications occurred in 18 cases (7 per cent): cholangitis in 4 (1·6 per cent) and haemorrhage in 14 (5·4 per cent). Two patients (0·8 per cent) with acute bleeding following ES died; in one of these surgery had been performed to arrest the haemorrhage, but the patient died 3 days after operation of hepatorenal failure. The other complications were treated conservatively without mortality.