Aim. To study the effects of long-term eprosartan treatment efficacy on myocardial structure and function in patients with essential arterial hypertension (EAH), and the association of these effects with structural polymorphism of angiotensin II type 1 receptors (AT2RI). Material and methods. The study included 121 males with Stage II-III EAH (WHO/ISH, 1999), mean age 49.09±8.34 years, with disease duration of 2-15 years. Central hemodynamics parameters and left ventricular myocardial mass (LVMM) were assessed by echocardiography (EchoCG) method. Left ventricular hypertrophy (LVH) was identified, according to the values of LVMM and LVMM index (LVMMI). LVH was diagnosed in LVMMI >134 g/m2. LV diastolic filling was assessed with Doppler EchoCG, by peak rates of early and late filling, and their ratio. Endothelial function was investigated with Doppler ultrasound. Prevalence of alleles and genotypes of polymorphic fragments (A1166C) of angiotensin II type 1 receptor gene was studied. The association of A/C polymorphism with hemodynamic parameters, LVH markers, endothelial function (EF), and eprosartan monotherapy efficacy, was also investigated. Results. A significant prevalence of A-allele and AA-genotype of AT1RII gene A1166C-polymorphic marker was observed. AC+CC genotypes were associated with more severe LVH, LV diastolic dysfunction, and EF disturbances. With equally high antihypertensive efficacy of 3-month eprosartan therapy, only AA-genotype patients demonstrated substantial LVH regression and complete normalization of vasoregulatory EF. Conclusion. Eprosartan demonstrated high antihypertensive efficacy in all participants. But only among AA-genotype patients, substantial LVH regression and complete normalization of vasoregulatory EF was observed during 3-month eprosartan therapy.