The aim of the study was to develop and evaluate the effectiveness of personalized therapy forpatients with diabetes mellitus type 2 (DM) and obesity based on the study of rs5219 polymorphism of KCNJ11gene. The study involved 120 women with DM and obesity I-II degree. Genotyping was performed in patients using allele-specific amplification with the detection in real time. Depending on the genotype of KCNJ11 gene patients with DM and obesity received different treatment and were divided into 2 groups (40 patients in each): group A (C/T genotype) received standard low-calorie diet + metformin 2000 mg/day and group B (T/T genotype) received a personalized diet + vitamin-mineral complex (VMC) + metformin 2000 mg/day. Results of the study of rs5219 polymorphism of KCNJII gene in patients with,DM and obesity have shown that 49% of them were carriers of the mutated T allele in the heterozygous form and 37% - in the homozygous variant. It has been found that reducing of calories in a diet promoted weight loss in patients with DM and obesity mainly due to lean body mass in Group A and in Group B - mainly due to the fat component. A significant decrease in blood glucose under complex therapy was observed in both groups. However, after treatment in group B blood glucose levels were significantly lower than in group A. Thus, personalized therapy of patients with DM and obesity should be based on molecular genetic studies that will allow to improve the efficiency of therapeutic measures in these diseases.