Currently, the percentage of non-specific myocardial lesions of non-inflammatory genesis has significantly increased in the structure of cardiovascular diseases in children and adolescents. Cardiomyopathies are a cluster of myocardial diseases that have become more of interest by cardiologists, morphologists, geneticists, and cardiac surgeons. Cardiomyopathies in children are regarded as a severe pathology characterized by a progressive course, resistance to therapy, and result in an unfavourable prognosis. The current article presents data from international publications dedicated to cardiomyopathy diagnostics in children. This article deals with terminology issues in compliance with international disease classification, primary diagnostic criteria of non-coronary myocardium pathology, and modern methods of diagnostics and pharmacotherapy.