The use of continuous interstitial glucose measurement systems (CGM) has revolutionized the management of patients with diabetes for 15 years. This is true both for professional use (diagnostic CGM) and personal use for patients (therapeutic CGM). The role of health professionals - general practitioners, diabetologists, nurses, dieticians - is important to coordinate, with a specific role for each. The clinical situations are all different and the systematic analysis of the data has ideally to be carried out with the participation of the patient. These devices allow significant improvements in glycemic control, making this technology one of the most important advances in diabetes for many years.