An isolated, centroblastic lymphoma developed in a 25-year-old female liver transplant recipient in her liver graft a few months after transplantation. Her immunosuppressive therapy consisted of antithymocyte globulin, cyclosporin, corticosteroids and, periodically, azathioprine. Chromosome analysis showed the tumor to be of female origin, thus excluding the possibility of transfer from the male donor. The tumor cells expressed EBV nuclear antigen (EBNA). The tumor was located in the left lobe of the liver. It was successfully removed 11 months after transplantation by a hemihepatectomy following a very brief combined chemotherapy course, and was then found to be replaced by necrotic tissue. No further treatment for lymphoma was given, and the patient is now free from lymphoma 3 years after transplantation.