Two cases are presented of liver transplantation in adult patients with fulminant liver failure using grafts from incompatible blood group donors due to the urgency of the situation. The patients evolved well as first but later both developed ischemia and necrosis of the bile tract secondary to severe rejection. It is concluded that the use of incompatible grafts can save the patient's life in acute irreversible liver failure, but in most cases retransplantation may be necessary as the definitive treatment of postoperative complications.