The pathologic specimens (n = 118) and hospital course pertinent to each of 62 adult liver allograft recipients were reviewed. Biopsies and retransplanted organs were obtained at the discretion of the surgical team on the basis of the postoperative clinical course (less than 1 day to greater than 12 years after transplantation), and final interpretation of the pathologic material was based on a correlation of all available data. Most of the specimens (n = 85) were obtained within the first 2 months, and diagnoses in this time period included rejection, biliary obstruction/cholangitis, vascular injury, herpesvirus and cytomegalovirus hepatitis, graft necrosis, and functional cholestasis. Thereafter, rejection and recurrent or primary viral hepatitis were the major causes of graft dysfunction. Histologically, hepatic rejection is manifested by a cellular mediated injury of hepatocytes and bile ductules and a spectrum of vascular lesions in medium-sized hilar arteries. Morphologic changes of biliary duct obstruction and viral liver disease were at times difficult to differentiate from rejection. Two pretransplant disorders, type B viral hepatitis and the Budd-Chiari syndrome, recurred in grafted organs. Although interpretation of pathologic material may be difficult at times, it frequently is helpful in planning an approach to management of liver allograft recipients.