A multi-institutional study to evaluate the efficacy, clinical application, and safety of extracorporeal shock-wave lithotripsy (ESWL) with the Dornier HM-3 or HM-4 lithotripter for bile duct calculi (BDC) was initiated in September, 1987. Symptomatic patients who entered into this prospective trial had BDC in the common bile duct and/or the intrahepatic, cystic or lobar ducts of the liver that were inaccessible or untreatable by papillotomy or percutaneous stone extraction. The study excluded gallbladder stones. Nasobiliary (54.4%) or transhepatic catheters (10.5%) and T-tube or cholecystostomy tubes (17.5%) or combinations (14.0%) permitted access for radiographic contrast to allow fluoroscopic monitoring of stone position and fragmentation. Exclusion criteria included pregnancy, failure to localize the stone, disturbances of coagulation, pacemakers, or vascular aneurysms or large bones that lie in the focal axis of the shock waves. Eleven institutions treated 42 patients (23 male, 19 female) with BDC; age range was 25 to 95 years (mean ± SD, 73.5 ± 13.8) and ASA risk category was 1 to 4 (mean, 2.3 ± 0.8). Fourteen patients (33.3%) had a single BDC; 28 had 2 to 8 stones (mean, 2.7 ± 1.8) ranging in size from 6 mm to 30 mm (mean, 18.5 ± 6.4). The majority (66.7%) of patients were postcholecystectomy. The 42 patients received 57 ESWL treatments consisting of 600 to 2400 shocks per treatment (mean, 1924 ± 289) at 12 to 22 kV (mean, 18.5 ± 1.9) administered over 20 to 125 minutes (mean, 52.9 ± 20.8). General anesthesia was used in 32% of the treatments; the majority were treated with epidural or regional block (42.1%), local infiltration (28.1%), or intravenous sedation (38.6%). Fifteen patients (35.7%) required two ESWL treatments. Stone fragmentation occurred in 94.6% of evaluable patients and in 90.4% of ESWL treatments, respectively; however, BDC fragments remained in 59.5% of patients 24 hours after treatment (diameter ≤ 3 mm, 12%; 4 to 9 mm, 16%; ≥ 10 mm, 68%). Some patients (50%) required adjunctive procedures to achieve stone removal that included endoscopic extraction (n = 10; 47.6%), biliary lavage (n = 8; 38.1%), endoscopic bile duct prosthesis (n = 1; 4.8%), and operation (n = 2; 9.5%). ESWL treatment complications during hospitalization were observed in 15 patients (35.7%) and were present in four (9.5%) at discharge. Complications included macrohematuria (5%), biliary pain (15%), biliary sepsis (5%), hemobilia (10%), ileus (2.5%), and adverse pulmonary changes (7.5%). One patient developed pancreatitis before ESWL at ERCP that resolved prior to discharge. At discharge, 73.8% of patients were stone free. This interim report suggests that ESWL successfully fragmented BDC and, with the adjunctive techniques used in one half of the patient population, resulted in the elimination of stones from three fourths of treated patients at the time of hospital discharge. ESWL permitted successful elimination of BDC with moderate rates of morbidity and no deaths for these high-risk patients who were otherwise untreatable by conventional techniques.