Telemedicine can be defined as the delivery of healthcare services, where distance is a critical factor, by all healthcare professionals using information and communication technologies for the exchange of valid information for diagnosis, treatment and prevention of disease and injuries, research and evaluation, and for the continuing education of healthcare providers, all in the interest of advancing the health of individuals and their communities. Such a wide definition includes many health care activities and a large number of applications have been tried, with variable degrees of interaction between all the players in the health care system. This review, starting from the need and opportunity that we are now facing to capitalize the great technological improvements in the field of information and communication technologies to improve also our health services, will illustrate the history, classification and main field of application of Telemedicine. Lastly, the available data on the application of Telemedicine for patients with respiratory diseases will be reviewed.