Essential thrombocythemia, a subcategory of chronic myeloproliferative disorder, is characterized by absolute thrombocytosis due to excessive clonal proliferation of platelets, hyperaggregability of platelets and increased incidence of thrombosis and hemorrhage. Essential thrombocythemia may cause frequent vascular thrombosis, but it can be a rare cause of acute ischemic heart diseases such as acute myocardial infarction without atherosclerosis, unstable angina and angina pectoris. We report a case of essential thrombocythemia complicated by acute myocardial infarction. A patient with a previous history of vascular thrombotic complications (such as transient ischemic attack and deep vein thrombosis) was managed with 2.8 million units of intravenous urokinase, antiplatelet agent, ACEI, antianginal medications and hydroxyurea. There were clinically remarkable improvements and no further episodes of thrombotic ischemic vascular complications, including acute myocardial infarction.