We report a rare case of idiopathic thrombocytopenic purpura (ITP) associated with acute myocardial infarction (AMI). A 72-year-old woman with hypertension and hemorrhoids was admitted because of chest pain, severe anemia (RBC 340 x 10(4)/microliter, Hb 5.4 g/dl, Ht 21.7%) and thrombocytopenia (0.2 x 10(4)/microliter). AMI was diagnosed by electrocardiogram (ST elevation and negative T in V2-5), echocardiogram (hypokinesis in anteroseptal wall) and laboratory (CPK 470 U/l) findings and was treated with only blood transfusion. Chest pain disappeared the day after admission, and neither heart failure nor arrhythmia occurred. Based on bone marrow findings (hyperplasia of erythroblast and megakaryocyte), endoscopic (internal hemorrhoids) and laboratory (antiplatelet antibody positive, platelet associated IgG 257.8 ng/10(7) cells) findings, iron deficiency anemia and ITP were diagnosed. Anemia improved after blood transfusion, but thrombocytopenia (< 1.0 x 10(4)/microliter) without active bleeding continued after steroid and gamma-globulin therapy. At discharge, electrocardiogram showed a negative T in I, aVL and V2-5, and T1 and BMIPP myocardial scintigram showed defects in the anteroseptal and apical wall.