Left ventricular noncompaction (LVNC) is a rare congenital abnormality resulting from an arrest of the normal process of myocardial compaction. LVNC has been known as a disease of infants, however, some surgical cases of LVNC in adult have been reported. A 61-year-old man who was diagnosed as dilated cardiomyopathy due to LVNC was admitted to our hospital because of dyspnea. Echocardiography revealed severe mitral regurgitation and diffuse left ventricular hypokinesis, and the hypokinetic wall consists of a thin compacted epicardial layer and a thicker noncompacted endocardial layer. Mitral valve replacement using a mechanical valve and cardiac resynchronization therapy were performed. The patient was easily weaned from cardiopulmonary bypass with medium-dose inotropic support and scheduled intra-aortic balloon pumping( IABP). Postoperative course was uneventful, and he was discharged in good condition on the 29th postoperative day.