Noncompaction of the left ventricular myocardium is a morphogenetic abnormality involving loss of compaction of the myocardial fiber meshwork during intrauterine life. It is an extremely rare condition, accounting for only 0.05% of the cases evaluated in databanks. It has been described in both genders, in many ethnic groups and at different ages. Recently published studies of case series have shown a high mortality rate among these patients during follow-up of up to 48 months. Many cases have so far been misdiagnosed due to poor knowledge of the findings relating to this syndrome. There needs to be an attempt at early and accurate diagnosis, because of the need to investigate the patients family upon such diagnosis, and today this can be achieved using echocardiographic criteria.