The effect of the anti-cell adhesion molecule antibodies, anti-ICAM-1 (1A29) and anti-LFA-1 (WT1), on rat liver transplantation was investigated. Livers from ACI rats were transplanted into Lewis rats by Kamada's method and during the recipient operation 1A29 1 mg/kg, and WT1 1 mg/kg were administered intravenously to one group of rats (treated group). The survival time of the treated group was significantly longer than that of the untreated group, but permanent unresponsiveness could not be induced. Postmortem examination revealed little histological evidence of acute rejection in treated rats, in which the main cause of death was thought to be chronic rejection.