Ten patients with the syndrome of non-ketotic hyperosmolar coma are described. The mean age of the patients was 62.3 +/- 17.12 years. One patient was 16 years old. In 9 cases the patients had type II diabetes, one had type I diabetes. In 7 cases the coma was the first sign of diabetes. The factor predisposing in most cases was infection. In the treatment-acting insulin and hypotonic solutions were given. In 2 cases clinical signs of the DIS syndrome were observed manifesting themselves with local changes, including mental disturbances. Heparin was given with good effect. Three patients (30%) died in hospital. The cause of death was serious disease associated with this coma: pancreatitis and myocarditis, purulent bronchopneumonia, myocardial infarction.