The state of prediabetes comprises two types of impairment of carbohydrate metabolism: impaired fasting glycemia and impaired glucose tolerance. According to International Diabetes Federation at present number of patients with prediabtes is almost 2 times greater than that of patients with diabetes. Risk of development of diabetes and cardiovascular complications in patients with prediabtes is 2 times higher than in persons with normal blood glucose level. Impaired glucose tolerance is also one of main components of metabolic syndrome. For prevention of risk of development of diabetes and cardiovascular complications besides life style changes it is necessary to influence insulin resistance and normalize carbohydrate metabolism. When life style changes are ineffective the use of antihyperglycemic drugs is essential. Antihyperglycemic preparations metformin, acarbose, thiazolidinediones do not affect function of pancreatic beta-cells and do not cause hypoglycaemia. This allows to use these drugs in patients without diabetes but having insulin resistance and prediabetes. Therapeutic effect of metformin and rosiglitazone is related to improvement of sensitivity to insulin in insulin dependent tissues, suppression of glyconeogenesis in the liver, and enhancement of pancreatic beta-cells function. Action of acarbose is based on local inhibition of intestinal enzyme alpha-glycosidase, what leads to diminishment of postprandial hyperglycemia peak. Results of DPP, STOP-NIDDM and DREAM trials have demonstrated high efficacy of antihyperglycemic preparations in prevention of type 2 diabetes.