The Long Beach, California, Emergency Mobile CAre System is a successful example of a major clinical engineering system. This system became operational within the city of Long Beach in 1972 and effectively coordinates and utilizes the resources of four hospitals, the fire department, private ambulance firms, and five paramedic units. This total clinical engineering system includes: radio and telephone voice and ECG communications; hospital base station with ECG and heart rate display and recording; satellite hospital centers; portable paramedic monitors and defibrillators; a transportation system; and, a data collection and retrieval system for system performance evaluation. This paper presents a description of the system and a summary of the data collection methods used to evaluate the performance of the system. In thirty-four months of operation, the paramedic units responded to over 25,000 calls. Approximately 266 patients require cardiopulmonary resuscitation each year. It is assumed that these services are provided only in life-threatening episodes where the patient would not survive without such emergency treatment. Analysis of this category shows a survival rate of 15% or 3 to 4 lives saved per month from CPR services alone. The number of additional lives saved due to reduction of shock and other life-threatening complications has yet to be determined.