The article presents the data on the assessment of cognitive function in young patients with diabetes type 1 and identification of possible risk factors. The presence of hypoglycemia, diabetic retinopathy has an impact on the state of cognitive functions. Patients receiving insulin therapy based on analogues of human insulin have significantly better performance in cognitive function. Patients receiving a daily dose of insulin more than 60 IU have significantly worse performance in cognitive function according to neuropsychological tests, compared with the group that received daily insulin dose of less than 40 IU. It may also be due to the large number of patients, who have hypoglycemic events.