Fragmentation of bile duct stones by mechanical, electrohydraulic, and laser intraluminal lithotripsy has greatly facilitated the ability to remove stones that are otherwise difficult to remove by standard manipulative techniques. Even these approaches fail when stones lack access or are impacted within the biliary tree. Extracorporeal shock-wave lithotripsy (ESWL) was evaluated in the United States in a multicenter trial with 56 patients. Stone fragmentation occurred in 91 percent of patients and duct clearance in 79 percent. Adjunctive procedures were used in 54 percent. Two ESWL treatments were required for fragmentation in 28 percent. Complications were mild and relatively infrequent. Hemobilia (8 percent), gross hematuria (6 percent), and biliary sepsis (4 percent) occurred less frequently than expected. There were no deaths during the 1 to 31 days of hospitalization (mean 9 days). We conclude that ESWL is a safe and effective adjunct to the treatment of difficult-to-remove bile duct stones under the conditions observed in this trial.