Aim: To investigate the features of changes in serum homocysteine (Hcy) levels in patients with T2DM depending on the presence or absence of retinal damage. Materials and Methods: We observed 77 patients with T2DM. Patients were divided into two groups: group 1 included 45 patients with T2DM and diabetic retinopathy (DR), group 2 included 32 patients with T2DM without DR. The level of Hcy concentration and B vitamins (vitamin B1, B6, B9, B12) was determined in blood serum. Results: Proliferative and preproliferative stages of DR were more frequently detected in the examined patients with T2DM (in 44.4% and 26.7% of patients, respectively). Proliferative retinopathy with complications was diagnosed in 17.8% of patients, while nonproliferative retinopathy with maculopathy was diagnosed only 11.1% of cases. In patients of both groups, a decrease in the levels of B vitamins in the blood serum was detected, which was detected against the background of an increase in the level of homocysteine in the blood serum in these patients. Conclusions: In patients with type 2 diabetes and DR, a decrease in the level of B vitamins was found against the background of an increased concentration of homocysteine (43.5±0.9 mkmol/l – p<0.001) in the blood serum, which proportionally increases with the progression of retinal damage in these patients.