A 53-year-old male patient who had suffered from acute myocardial infarction before a week was admitted due to postinfarction angina A mobile pedunculated left ventricular thrombus of 2.0-cm diameter which was overlooked in cardiac catheterization and ventriculographic study was diagnosed with transthoracic two-dimensional echocardiography. There was no exact clinical finding of left ventricular aneurysm and the thrombus was placed in the akinetic and hypokinetic apical portion. For preventing systemic embolism that was removed through a left ventriculotomy just prior to coronary artery bypass grafting.