Cardiomyopathies in children are rather rare, but extremely severe disorders that are little known in practical healthcare. Many of them are a cause of sudden death and they are familial. By using their findings and the data available in the literature, the authors describe the etiology, pathogenesis, morphology, and clinical presentation of dilated, hypertrophic, arhythmogenic right ventricular, histiocytoid cardiomyopathies, as well as the non-compact myocardium, and a type of cardiac connective tissue dysplasia. By keeping in mind the frequency of inheritance of cardiomyopathies, it is necessary to improve the diagnosis of these diseases not only for timely treatment, but also medical genetic counseling.