Type 2 diabetes is a serious social problem. In pharmacotherapy of the disease, the recommended drug of the first choice is metformin, which has been available on the market for 60 years now. The main effect of metformin is antihyperglycemic activity through several mechanisms of action. Metformin exerts non-glycemic effects as well. As a result of long-lasting treatment, metformin substantially reduces the cardiovascular risk. The new therapeutic indication for metformin is prediabetes.