Health authorities currently have high expectations for telemedicine (TM), as it addresses several major challenges: to improve access to healthcare (especially for patients in underserved or remote areas); to overcome the scarcity of specialists faced with epidemic disease; and to reduce the costs of healthcare while improving quality. The aims of TM in the field of diabetes differ according to the type of diabetes. In type 1 diabetes (T1DM) associated with complex insulin regimens, the goal of TM is to help patients achieve better control of their blood glucose levels through accurate adjustment of insulin doses. In type 2 diabetes (T2DM), while therapeutic adjustments may be necessary, improvement in blood glucose control is based primarily on behavioural changes (reduced calorie and carbohydrate intakes, increased physical activity). Many TM studies focusing on management of blood glucose levels have been published, but most failed to demonstrate any superiority of TM vs traditional care. While previously published meta-analyses have shown a slight advantage at best for TM, these meta-analyses included a mix of studies of varying durations and different populations (both T1DM and T2DM patients, adults and children), and tested systems of inconsistent quality. Studies published to date on TM suggest two currently promising approaches. First, handheld communicating devices, such as smartphones, loaded with software to apply physicians' prescriptions, have been shown to improve glycaemic control. These systems provide immediate assistance to the patient (such as insulin-dose calculation and food choice optimization at meals), and all data stored in the smartphone can be transmitted to authorized caregivers, enabling remote monitoring and even teleconsultation. These systems, initially developed for T1DM, appear to offer many possibilities for T2DM, too. Second, systems combining an interactive Internet system (or a mobile phone coupled to a remote server) with a system of communication between the healthcare provider and the patient by e-mail, texting or phone calls have also shown certain benefits for glycaemic control. These systems, primarily aimed at T2DM patients, generally provide motivational support as well. Although the individual benefits of these systems for glycaemic control are fewer than with smartphones, their widespread use should be of particular value for overcoming the relative shortage of doctors and reducing the health costs associated with a disease of such epidemic proportions.