Background/Aims: With advanced endoscopic techniques and lithotripsy devices, virtually all patients with common bile duct(CBD) stones can be successfully managed endoscopically. Nevertheless several factors are believed to make the endoscopic removal of CBD stones more difficult. Our intent was to evaluate the success rate of endoscopic removal of CBD stones and to determine which factors significantly influence the success rate. Methods: We retrospectively reviewed 232 patients who were submitted to endoscopic treatment (including mechanical lithotripsy and electrohydraulic lithotripsy) for removal of CBD stone during a recents 3 years period. Success was defined as complete stone removal within 3 endoscopic sessions considering the endoscopic techniques, patients compliances and cost effectiveness. Predictive factors such as size and number of stones, Billroth II operation, periampullary diverticulum, and the presence of cholangitis or pancreatitis were evaluated. Statistic analysis was performed by logistic discriminant analysis and CHAID methods. Results: The overall success rate in all 232 patients was 93.5%. Complete stone c1earance from the bile duct was achieved after a single session in 155 patients(66.8%) and after two sessions in 43 patients(18.5%), while 19 patients(8.2%) required three sessions. Only the size of stones and Billroth II operation were identified as significant predictors of failure of endoscopic stone removal. The numbers and sizes of stones, and Billroth II operation had an increasing effect on the frequency of endoscopic sessions required for complete stone removal. Complications were related mainly to endoscopic sphincterotomy, such as bleeding in 14(6.0%), one of whom required operation for hemostasis. Pancreatitis developed in 3 patients(1.3%). There were no death. Conclusions: Endoscopic stone removal should be recommended as first-line therapy because of its safety and effectiveness. Consideration about the predictive factors such as size, number and Billroth II operation for the outcomes of endoscopic stone removal may be useful in deciding treatrnent options for CBD stones. (Korean J Gastroenterol 1996; 28:537 - 548)