A 38-year-old man presented with an acute anterior myocardial infarction (MI) and was subjected to thrombolysis. Echocardiography and cardiac catheterization revealed a mass in the left atrium that was considered to be a myxoma. The coronary arteries appeared normal on angiography. The left atrial mass was removed surgically without complication. Histopathologic examination confirmed the diagnosis of the myxoma. Coronary embolism secondary to the myxoma was thought to be the cause of the MI.