Euglycaemia is characterized by fasting plasma glucose levels of 70–100 mg/dl, while dysglycaemia is characterized by fasting plasma glucose levels of ≥100 mg/dl. The term dysglycaemia covers three conditions: impaired fasting glucose (IFG), impaired carbohydrate tolerance (IGT) and type 2 diabetes mellitus. The identification and classification of dysglycaemia and ways to treat it in order to prevent complications are discussed.