Orthotopic liver transplantation (OLT) has been used with increasing frequency as a definitive treatment for end-stage liver disease. Whereas the spectrum of pathology in the early posttransplant period is well documented, the clinicopathologic features of patients with late hepatic dysfunction are less clearly defined. In a series of 100 OLTs we identified 12 patients with progressive liver dysfunction 4 months after transplantation. Four patients succumbed rapidly to fulminant hepatitis 4 to 6 months following transplantation, three of whom had recurrent hepatitis B infection. One patient lost two successive grafts owing to hepatitis C. Liver biopsies were diagnostic for hepatitis in all cases. The outcome of the remaining eight patients with late hepatic dysfunction was grim. Their clinical courses were notable for intractable and progressive cholestasis. Five patients died and two others required retransplantation. Only one patient responded to increased immunosuppression with FK506. Ductopenia was a common feature of liver biopsies in these cases, but severe ductopenia (vanishing bile duct syndrome) was seen in the liver biopsies of only four patients. In contrast, occlusive arteriopathy and secondary ischemic changes were ubiquitous. In summary, the liver biopsy is a useful adjunct in the diagnosis of late OLT dysfunction, particularly in distinguishing recurrent viral hepatitis from chronic graft rejection. Centrilobular ischemic changes occur frequently in chronic rejection, whereas ductopenia may be difficult to document consistently.