Background: Level of intelligence influences compliance of diabetic patients and their active and conscious participation in self-care. A potential association between IQ and surrogate efficacy markers of type 2 diabetes mellitus (T2DM) treatment has not been studied in Russia.Aim: To assess potential association between level of intelligence, glucose control, blood pressure (BP) control and obesity in T2DM patients.Materials and methods: This cross-sectional study included 161 T2DM patients (28 males, 133 females) aged from 37 to 79 years with diabetes duration from 0,5 to 30 years. All patients underwent standard clinical and laboratory assessment, including glycated hemoglobin (HbA1c) measurement and were seen by a psychiatrist to diagnose possible depressive and cognitive disorders according to International Classification of Diseases-10 criteria. Each participant underwent psychometrical assessment, including Hachinski Ischemia Scale and a battery of cognitive tests. IQ was measured with Wechsler Adult Intelligence Scale (WAIS).Results: Mean (± SD) IQ was 100,6 ± 14,9, which corresponds to average IQ. There was no correlation between IQ and patients age. There were no differences in IQ in T2DM patients from various bodyweight categories. Correlation between HbA1c and IQ in the whole group was non-significant (r = -0,13). Only patients with high and very high IQ (≥ 110) had lower HbA1c than the rest of the group (with IQ < 110): 8,1 ± 2,4 и 8,9 ± 1,9%, respectively (р < 0,05). Level of education did not influence glucose control, BP and body mass index (BMI); HbA1c, BMI and BP values in patients with primary and higher education was virtually similar.Conclusion: Level of intelligence of T2DM patients does not contribute to risk factor control, such as bodyweight and BP. In majority of T2DM patients, glycemic control does not depend on their IQ and educational level; significantly better glucose control is achieved only by patients with higher IQs. The most important contributor to decrease of IQ in T2DM patients is not their age but rather chronic brain ischemia, i.e. cerebrovascular disease.