A 28-year-old male was diagnosed as aplastic anemia in 1983. He maintained on corticosterone with a large transfusion requirement for being resistant to other therapies, and combined with hemochromatosis at 20-year-old. In February 1994, he was admitted to the hospital for consideration of BMT. Echocardiogram was normal on admission. He was transplanted with bone marrow from his HLA-matched MLC negative sister following contained of TLI (7.5 Gy) and CY 50 mg/kg for four days on March 10 1994. Disturbance of consciousness appeared, an echocardiogram showed severe pericardial effusion on day 1 after BMT. He was diagnosed cardiac tamponade, pericardiocentesis was done immediately and 100 ml pericardial effusion was removed. Transiently he became alert, however, irreversible cardiac arrest occurred on day 2. Postmortem examination revealed thickened left ventricles with intramyocardial hemorrhage. It seems necessary to reduce CY, or substitute it with anti-thymocyte globulin (ATG) or TBI etc. for BMT in aplastic anemia accompanied by hemochromatosis.