A seven-year-old girl underwent heart transplantation because of progressive congestive heart failure resulting from familial dilated cardiomyopathy. Her parents were second cousins to each other and her brother had died of dilated cardiomyopathy. Her symptoms of congestive heart failure began four months before the transplantation and became gradually worse. Left ventricular ejection fraction was 10 to 20% echocardiographically, and mitral and tricuspid valve regurgitation were present. Her condition of NYHA IV was not improved by treatment with dobutamine infusion and isosorbide dinitrate. She was transported to the Primary Children's Medical Center in Utah, USA, on July 22, 1991 in critical condition to undergo heart transplantation. Despite treatment with amrinone and additional catecholamines, she became semicomatose due to ischemic liver injury on July 24, 1991. A donor became available on July 25, 1991, and the transplantation was performed. Cardiac ischemic time was 97 min. Although she had transient OKT3 monoclonal antibody-related encephalopathy on her fifth postoperative day, she recovered normally. She had moderate rejection on the 20th postoperative day and mild rejection on the 79th and 149th postoperative days. She has had no significant infectious diseases. The baseline examination performed three months after heart transplantation revealed no abnormal findings on her coronary arteriogram. She returned to Japan and has been attending elementary school. The annual examination of her transplanted heart showed neither stenosis nor occlusion in her coronary angiogram. She has been receiving cyclosporine, azathioprine, and a low dose of prednisone as an immunosuppressive regimen. If she does not exhibit rejection, the use of steroids will be decreased or discontinued.