Isolated noncompaction of the ventricular myocardium (INVM) is an unclassified cardiomyopathy and is thought to be due to arrest of myocardial morphogenesis. Left ventricular failure and ventricular arrhythmias may occur in approximately half of the patients and account for half of the death in this disorder. In this report, we describe a patient with INVM in whom cardiac resynchronization and cardioverter defibrillation therapy was effective for the improvement of left ventricular function and for the prevention of ventricular arrhythmias.