Management of type 1 and type 2 diabetes mellitus is getting complex with the apparition of new treatments, but also new technologies. Among these, continuous glucose monitoring systems (CGMS) lead to a better glycemic control and less hypoglycemia in type 1 diabetic patients. Studies are scarce in type 2 diabetes but also seem to show a benefit, particularly in patients using insulin. Nevertheless, type 2 diabetic patients taking advantage of CGMS must be better defined. In any case, a multidisciplinary approach to the use of CGMS and interpretation of data is warranted.