A 77-year-old woman was admitted to this hospital for evaluation of chest pain for 3 days. On physical examination, icteric sclerae, inspiratory crackles on both lower lung field and normal heart sounds were observed. Electrocardiograms showed pathologic Q waves with ST elevations in the precordial leads(V1-V4). Chest X-rays showed mild pulmonary edema with anteroseptal wall akinesia. Cardiac enzyme studies were compatible with AMI. Hematologic investigation revealed severe thrombocytopenia and microangiopathic hemolytic anemia. Coagulation profiles were normal. Coombs test, sucrose lysis test, anti-platelet antibody and antinuclear antibody were all negative. Urinalysis showed albuminuria(+++) and microscopic hematuria. Initial therapy with aspirin, nitrate, morphine and prednisolone was started. Ten hours after admission, she developed agitation, aphagia and confusion with progression to coma. Computed tomography of the brain was normal. Five units of fresh frozen plasma were infused. After one day, platelet counts slightly increased. But cardiogenic shock ensued and she died despite cardiopulmonary resuscitation. AMI has not been reported in association with TTP. This patient had no risk factors for coronary artery disease and no previous history of angina. TTP was clinically diagnosed with confidence by excluding other known cause of microangiopathic hemolytic anemia with thrombocytopenia. Coronary angiogram and bone marrow examination could not be performed due to a rapidly fatal course. The etiology of AMI in this patient was not confirmed, but clinical evidence strongly supported etiologic association with TTP.