Telemonitoring, is defined as the use of information technology to monitor patients at a distance. This literature review suggests that the most promising applications for telemonitoring is for chronic illnesses such as cardiopulmonary disease, asthma, and heart failure in the home. Fetal heart rate monitoring and infant cardiopulmonary functions have also been monitored at a distance, as well as coagulation, or the level of activity of elderly people, assessed by the intelligent home monitoring devices. Hospitals, clinics, and prisons all have used telemonitoring, as have ambulances equipped with systems connected to the receiving hospital. Telemonitoring allows reduction of chronic disease complications thanks to a better follow-up; provides health care services without using hospital beds; and reduces patient travel, time off from work, and overall costs. Several systems have proven to be cost effective. Telemonitoring is also a way of responding to the new needs of home care in an ageing population. Real-time monitoring of patients in ambulances reduces the time to initiate treatment and allows the emergency crew to be better prepared. The obstacles to telemonitoring development include the initial costs of systems, physician licensing, and reimbursement. In the future, virtual reality, immersive environments, haptic feedback and nanotechnology promise new ways in improving the capabilities of telemonitoring.