Between 1983 and 1988, endoscopic sphincterotomy was attempted on 1000 consecutive patients with a clinical diagnosis of bileduct stones in a centre with a policy to establish immediate bileduct drainage for retained stones. Endoscopic cholangiography was successful in 985 patients, of whom 782 had visible stones and 203 had a dilated bileduct but no visible stones. Endoscopic sphincterotomy was successful in 975 of these patients, with eventual bileduct clearance in 674 of 772 patients (87.3%) with visible stones; immediate bileduct drainage was achieved in 160 of the 161 patients (99%) in whom bileduct clearance failed at the first attempt. Overall, 771 of 797 patients (96.7%) with visible bileduct stones had successful bileduct clearance or drainage. Complications occurred in 6.9%, with a 30-day mortality rate of 1.2%, but procedure-related mortality was only 0.6%.