In this report, our objectives are to introduce the term "ischemic cholangitis" as an etiologic designation and to describe its manifestations. Herein we use the label "ischemic cholangitis" as a collective term for ischemic bile duct necrosis, cholangitis caused by ischemia but without necrosis, and biliary fibrosis as a manifestation of ischemic damage. The condition was observed in 12 allografts, either at the time of retransplantation (9 cases) or at autopsy (3 cases). Ischemic cholangitis involved primarily perihilar extrahepatic and intrahepatic bile ducts. The findings included duct necroses (eight cases), strictures (four cases), and cholangiectases (four cases); some of these features coexisted. In addition, complicating ascending cholangitis and cholangitic abscesses were noted in three cases. Ischemic cholangitis was caused by hepatic artery thrombosis (in nine patients) or stenosis (in one) or by occlusion of parabiliary arteries by fibrointimal proliferations, probably attributable to old thromboses (in two, in conjunction with associated foam cell arteriopathy in one). Biopsy specimens before retransplantation or autopsy were obtained in 11 patients, only 1 of whom had an infarct as direct evidence of ischemia. Nine patients had evidence of biliary obstruction or bile flow impairment; in two cases, specimens were normal or nondiagnostic relative to cholangitis. Features of cellular rejection associated with the manifestations of bile flow impairment and ischemia were noted in five cases. Thus, biopsy features that suggest biliary obstruction, with or without cellular rejection, may be a manifestation of ischemic cholangitis. We conclude that ischemic cholangitis is an important cause of cholestatic graft failure but that this type of cholangitis is difficult to diagnose because of its misleading biopsy manifestations.