Efficacy and safety of pulsed dye laser lithotripsy was tested in 25 consecutive patients in whom bile duct stones could not be extracted after endoscopic sphincterotomy. The patients had one to six (mean, 1.8) bile duct stones (diameter, 10-35 mm; mean, 18 mm) located in the common bile duct (18 cases), the intrahepatic bile ducts (6 cases), or in a long cystic duct stump (1 case). Different approaches were tested depending on the presence of a T tube and on the localization of the bile duct stones. When a T tube was present (7 cases), the lithotripsy was performed under direct vision using a choledochoscope inserted through the T-tube tract. In 18 patients without a T tube in place, the lithotripsy was performed under fluoroscopy using a retrograde approach in case of common bile duct stones (14 cases) or under choledochoscopy using a percutaneous transhepatic approach in case of intrahepatic bile duct stones (4 cases). Fragmentation of all the bile duct stones and a complete bile duct clearance were obtained in all 11 cases with procedures performed under direct vision as compared with only 5 of 14 cases with procedures under fluoroscopic control. Moreover, 6 of the 9 failures using the latter approach were offered another session using a choledochoscope inserted through a percutaneous transhepatic tract and were also successfully treated. No complication related to the laser beam was noted. It is concluded that pulsed dye laser lithotripsy of bile duct stones (that are unable to be removed by standard endoscopic techniques) is safe and efficacious provided that it is performed under direct vision. Technical refinements are needed before this procedure can be reliably performed under fluoroscopy.