Hypothesis: Nontraumatic perforation of the bile duct in adults is rare, and the management of this condition should resolve the primary pathologic lesion. Design: Retrospective analysis of 11 patients who were diagnosed as having nontraumatic perforation of the bile duct. Setting: A public university medical center and a private university medical center. Patients: Five men and 6 women (median age, 64 years) with nontraumatic perforation of the bile duct were treated between September 1993 and May 2003. Interventions: Two patients with common bile duct (CBD) stones, who were initially diagnosed as having mediastinal abscess and subcapsular biloma, respectively, were treated by nonoperative management, ie, endoscopic sphincterotomy and percutaneous abscess drainage. The remaining 9 patients were treated surgically, which included an exploration of the CBD, placement of a T tube, and a liver resection. Main Outcome Measures: Initial manifestation, primary disease, perforation site, management, surgical morbidity, and mortality. Results: All patients had acute abdominal pain, which was caused by intraabdominal abscess in 7 patients, diffuse bile peritonitis in 3, and subcapsular biloma in 1. Their primary diseases were CBD stones in 7 patients, intrahepatic duct stone in 2, a choledochal cyst in 1, and phytobezoar with food stuff in the CBD in 1. Perforations occurred at the left intrahepatic duct in 9 patients, the CBD in 1, and the cyst wall in 1. All patients recovered, except 1 patient who expired owing to multiorgan failure because the operation could not be performed in time. Conclusions: Nontraumatic perforation of the bile duct should be suspected if perihepatic abscess or peritonitis is combined with biliary stone disease. The management of non traumatic perforation of the bile duct should include the eradication of the primary pathologic lesion and the control of abscess or peritonitis.