Death and disability from ischemic heart disease, trauma, and other medical emergencies may be reduced significantly by developing an Emergency Medical Services system based on training for the nonmedical population in basic life-support skills; this is particularly appropriate in high-density population centers where professional response time is complicated by confestion and traffic. A pilot project in New York City, which designed and implemented a first-response capability for medical emergencies in corporations, using employees in a system congruent with the fire warden plans in effect, was completed in May 1977. To obtain an initial assessment of the medical impact of such training and the effectiveness of such a medical emergency response system during the pilot phase, The Regional Emergency Medical Services Council of New York City, Inc., obtained reports from the 24 participating corporations on all reported medical and surgical emergencies occurring in the working environment. The authors conclude that this approach to development of a first response-capability can provide an effective community base for an effective Emergency Medical Services system in urban areas.