Telemedicine is a subset of telehealth. The role for telehealth in providing healthcare services in public health emergencies should be considered within the context of a changing social environment created by emerging technologies. The current state of the art with respect to the use of telehealth in public health emergencies is varied and somewhat rudimentary. Although the current role of telehealth in public health emergencies is limited and variable, there are several telehealth modalities in use, including real-time clinical videoconferencing, home telehealth, store-and-forward, public telephone systems, amateur radio, and web-based information. There is increasing use of informal telehealth modalities to provide support in emergency and disaster situations. With technologic advances, heightened emphasis on efficient allocation of scarce resources and cost-effectiveness, and protection of emergency responders, telehealth become an increasing important tool for the emergency managers of the future.