Aims: Hypoglycemia can be considered the most common complication of Diabetes Mellitus treatment. So far, controversial studies have been carried out to examine the impacts of hypoglycemia on the cognitive function. Methods: This study was conducted as case-control. The case group was 35 patients with Diabetes Mellitus Types I or II hospitalized in Imam Hussein Hospital, Tehran, Iran, who have experienced hypoglycemic attacks (glucose level below 70 mg/di). The control group consisted of diabetic patients hospitalized in hospital, but they had no history of hypoglycemia. As the blood glucose level became in normal range and the patients' Mental status became stable, the brain cognitive function was examined using Mini-Mental State test. Results: The mean age of the subjects in the case and control groups was 56.77, 53.73 years old, respectively. The mean cognitive score in the control and hypoglycemic groups was 29.09 and 25.29, respectively. The mean MMSE cognitive score was significantly diminished in the hypoglycemic group (p < 0.001). Conclusions: This study indicated that incidence of hypoglycemia in diabetic patients is associated with cognitive disorders. Further, there is a linear association between cognitive disorders and hypoglycemia, age and diabetes mellitus complication. (C) 2018 Diabetes India. Published by Elsevier Ltd. All rights reserved.