Acute T cell mediated rejection still occurs between 5% and 20% of adult liver transplants. Tacrolimus-based therapy seems superior to Cyclosporine-based therapy in preventing such episodes. Liver biopsy remains the gold standard for diagnosis and pulse corticosteroid therapy for treatment. The outcomes are usually favorable. Other forms of allograft rejection such as antibody-mediated rejection (acute or chronic) are more difficult to diagnose, and treatments are associated with poorer outcomes. Other forms of immunological allograft injury such as plasma cell hepatitis and idiopathic chronic hepatitis are probably unusual forms of allograft rejection. Withdrawal of immunosuppression in adults is not usually successful, although late complete withdrawal in pediatric recipients can be achieved more readily.