We report the case of a 6.5-year-old male who received an unrelated orthotopic liver transplant for hepatic failure and encephalopathy following non-A-non-B hepatitis and subsequently developed severe aplastic anemia. For treatment of his aplastic anemia, he received a successful marrow transplant from his 9-year-old genotypically HLA- identical sister following conditioning with cyclophosphamide 200 mg/kg and anti-thymocyte globulin 90 mg/kg. Significant veno-occlusive disease of the liver and graft-versus-host disease did not occur. The patient remains alive without clinical chronic active hepatitis or need for blood product therapy. His hematocrit is 36%, white blood cell count 9.7 x 10(3)/mm3, and platelet count 1.7 x 10(5)/mm3 almost 2 years after marrow transplantation.