Isolated noncompaction of the ventricular myocardium (INVM) is an unclassified cardiomyopathy and is thought to be due to arrest of myocardial morphogenesis. Although right ventricular involvement is not uncommon, the correct diagnosis is often difficult by echocardiography. In this report, we describe a patient with INVM in whom magnetic resonance imaging was useful to detect right ventricular morphological and functional abnormalities.