Telemedicine--the delivery of health care services to the underserved through communications technologies--has the potential to bring medical care to remote areas where health care is either inadequate or nonexistent. Telemedicine can be something as simple as a phone call, a network transmission of a radiograph or other diagnostic image, or, much more advanced, realtime video surgical consultations from anywhere on the globe. Telemedicine programs operate throughout Europe, Japan, and Australia. International programs, for profit and nonprofit, serve Asia, Africa, and the Middle East. The United States is also a major telemedicine developer, principally through government agencies such as the Department of Defense and the Office of Rural Health Policy, and, to a lesser extent, the private sector. But telemedicine in the United States has yet to prove itself economically viable, and it faces a number of political and regulatory barriers. Even more significantly, telemedicine's potential to increase overall health care spending by increasing access to health care has deterred private industry from investing heavily in it. In the short term, telemedicine's most important contribution to health care may be raising fundamental questions about United States health care policy.