Telemedicine is a remote medical practice which uses tools related to information and communication technologies (ICT). Since July 21, 2009, French law permits this new medical practice and the decree of October 19, 2010, indicates the main procedures (tele-consultation, tele-expertise, medical tele-surveillance, medical tele-assistance, tele-advice from the hospital call center) and the conditions of their implementation. Clinical research is the practice of clinical trials which have the aim of evaluating the safety and efficacy of a diagnostic method or a new treatment. Clinical research is the main purpose of the National Association of Telemedicine (ANTEL) and of its new official journal European Research in Telemedicine. This editorial is opening the first issue of our journal. Several examples can illustrate the importance of clinical research in telemedicine. In type 1 diabetes, after the first discordant results due to insufficient or weak methodologies, the French study TeleDiab 1 brought for the first time a clinical improvement over 6 months in patients followed-up remotely by Diabeo software and teleconsultation. The main medical service to patients was a decrease of complication risks due to a significant decrease of HbA1c. Nevertheless, the encouraging results of this pilot study need confirmation over a longer period (the TELESAGE study over two years). In chronic heart failure, the first results of two meta-analyses showed a significant 30% reduction in morbidity and mortality. However, these results were not confirmed by two, more recent, prospective and randomised studies. Most authors think that it is necessary to define several subgroups of patients with chronic heart failure in order to recognize patient subgroups who could benefit from telemedicine at home. The medical service to stroke patients brought by telemedicine is not open to debate. Telestroke allows patients away from neurology centres to benefit from emergency thrombolysis (less than 4h 30min after the first signs) treatment that can allow the total or partial regression of a neurological deficit. Other telemedicine applications have been able to demonstrate a medical service to patients, for example remote blood pressure self-monitoring at home in hypertensive patients, live interactive teledermatology, teledialysis by peritoneal dialysis at home or by haemodialysis by a remote satellite unit, etc. Teleradiology brings a medical service to patients if it is carried out according to international or national guidelines. Many other applications of telemedicine may be the subject of clinical research such as telegeriatry, tele-psychiatry, tele-surgery, tele-rhumatology, tele-obstetric, tele-pathology, etc.). Telemedicine practice can have a significant economical impact, particularly due to reductions in hospitalisation numbers. Risk factors due to telemedicine are beginning to be known. Clinical research on the medical service to patients followed-up by telemedicine can prevent risks.