It was investigated the influence of a diet supplemented with selenium on the clinicometabolic parameters and the activity of lipid peroxidation in 43 patients with Type 2 diabetes mellitus. It was indicated that under the influence of dietotherapy besides the decrease of glucose levels in capillary and venous blood, improvement of parameters of lipid metabolism, a reduction of malondialdehyde level and tendency to increase of glutathione peroxidase activity were observed. The results of investigations testify about sufficiently expressed efficacy of a diet supplemented with selenium in correction of oxidative stress and clinicometabolic parameters in this contingent of patients.