Arterial hypertension (AH) and obesity - risk factors for cardiovascular diseases and their complications, leading to high morbidity and mortality. These nosologies notedly linked, because have common etiological factors, pathophysiological mechanisms and genetic determination. The aim this research was to analyze the distribution of genotypes of the C825T polymorphism of β3-subunit G-protein gene (GNB3) according the degree of obesity and to assess the risk of obesity in patients with AH. Patients were divided into three groups according the degree of obesity. We used clinical, anthropometric, instrumental, molecular-genetic and statistical methods. The significance of differences of alleles and genotypes frequency was determined by test χ². For comparing the groups used nonparametric Mann-Whitney and Kruskal-Wallis tests. A value of p0.05 was considered significant. Our research showed high frequency of T allele carriers and C/T genotype among patients with hypertension and obesity (χ² = 27,976, p0.001). In our study we observed the absence of statistically significantly difference (p = 0.677) of distribution of genotypes and alleles in patients with AH according the degree of obesity. The risk of obesity in T allele carriers was in 2.2 times higher than in C allele carriers in patients with AH. In summary, our study showed association of C825T polymorphism of the GNB3 with obesity, but did not prove the association this with the degree of obesity i patients with AH.