Aim of the study was analysis of dependence of clinical picture and degree of severity of left ventricular hypertrophy (LVH) on polymorphism A/C of ATR1 gene in patients with hypertrophic cardiomyopathy (HCMP) and hypertensive disease (HD). With the method of polymerase chain reaction genotyping for polymorphic markers of A/C of ATR1 gene was carried out in 35 patients with HCMP and 33 patients with LVH developed at the background of long lasting HB. In the work we used clinico-instrumental methods of investigation (electrocardiography - ECG, echocardiography). It was revealed as result of the study that in HCMP type AA in comparison with type AC of ATR1 gene was associated with addition of arterial hypertension, presence of left ventricular outflow tract obstruction, greater severity of heart failure. In case of combination of HD with LVH type AA in comparison with types AC and CC of ATR1 gene is associated with more pronounced LVH.