Functional insulin therapy is a teaching approach of intensified insulin therapy. Its aim is to transfer to the patient the decisional process and the management of its insulin treatment, this according to the various acts of everyday life, and particularly meals. The principles of functional insulin therapy, the pedagogic approach, the benefits observed in type 1 diabetic patients (better diabetes control, and particularly decrease in the number of severe hypoglycaemic events) are briefly described - Nevertheless, to apply this functional insulin therapy in practice, requires a specific teaching program preferably ambulatory in real everyday life conditions, and carried out by a staff highly qualified in diabetology.