We report a successfully treated case of rapid progressive left ventricular (LV) thrombus with ischemic cardiomyopathy. Initially, the patient was scheduled to undergo only coronary artery bypass grafting. After two months, preoperative echocardiography revealed a previously undetected ball-like thrombus in the LV cavity. Surgical revascularization and thrombectomy were performed. No systemic embolism was associated with surgical manipulation during the perioperative period. Repeated preoperative evaluation for the presence of thrombus by transthoracic or transesophageal echocardiography is essential in cases of ischemic cardiomyopathy.