A b s t r a c tBackground: Hypoglycaemia is a condition that occurs when blood glucose levels fall below 3.9 mmol/L (70 mg/dL), while hypoglycaemic coma is usually associated with glycaemia around 1.1 mmol/L (20 mg/dL). Recurrent severe hypoglycaemia may result in permanent neurological disorders and also has a negative impact on the cardiovascular system. Aim:To evaluate the causes of severe hypoglycaemia in elderly patients with type 2 diabetes and coexistence of cardiovascular history. Methods:We analysed retrospectively the history of 33 elderly patients with type 2 diabetes and coexistence of cardiovascular history, who were admitted to our clinic due to severe hypoglycaemia with loss of consciousness. The mean age of the patients was 76.0 ± 11.1 years, and the mean duration of diabetes was 12.0 ± 9.8 years. Glycated haemoglobin (HbA1c) was measured and the prevalence of cardiovascular diseases and therapeutic procedures were evaluated. Results:In the group of patients with severe hypoglycaemia, the mean value of HbA1c was 6.3 ± 1.2% (44 ± 13.1 mmol/mol), which indicates a mean glucose value below 7.8 mmol/L (140 mg/dL). Ischaemic heart disease was diagnosed in 18 patients (eight had a history of myocardial infarction), and 22 patients had arterial hypertension. Severe hypoglycaemia requiring hospitalisation in elderly patients with type 2 diabetes and coexistence of cardiovascular history was related to insulin or sulfonylurea therapy. Conclusions:A low HbA1c level indicates inappropriate intensification of therapy and was associated with high risk of severe hypoglycaemic episodes in older people. The majority of severe hypoglycaemic episodes were observed in sulphonylurea or insulin-treated type 2 diabetic patients.