Isolated noncompaction of the ventricular myocardium (INVM) is a rare cardiomyopathy resulting from a failure of normal endomyocardial embryogenesis and it has been categorized as a form of unclassified cardiomyopathy. The disorder is characterized by excessively prominent trabecular meshwork with deep intertrabecular recesses. The disorder is sporadic, however familial incidence may occur. Clinical symptoms and prognosis of INVM may differ markedly, which range from a asymptomatic course to a severe cardiac disability. The method of choice to diagnose IVNM is echocardiography, which revealed mulitple prominent trabeculations with deep intertrabecular spaces communicating with left ventricular cavity in the middle and apical segments of left ventricle. The authors report a case of INVM in a family in which three adult members (a brother and two sisters) were found to be affected by this disorder. They were all asymptomatic. The diagnosis of the disorder was made first in the brother who is a 36-year-old man by transthoracic echocardiography (TTE) and multidetector CT (MD CT) in a process of preoperative evaluation for surgical treatment of low back intervertebral herniated disc. TTE and MD CT showed similar and peculiar findings of INVM. Echocardiographic screening in all first-degree relatives of this patients in order to identify asymptomatic patients, and demonstrated INVM in two elder sisters.