A prospective performance evaluation of EMTs caring for 2,938 consecutive ambulance cases was carried out. Patient information data, signs and symptoms, EMT diagnosis and disposition were all collected and analyzed. The EMT course time allotments were found to be roughly proportional to the incidence rates of the various diagnostic categories with the exception of drug and alcohol abuse and psychiatric problems, both of which occurred far in excess of their time allotments. EMT diagnostic accuracy varied considerably among diagnostic groups, tending to be higher among surgical problems than medical. Consistency of treatment was lower than expected and was one area where a change in the 81 hour course emphasis would markedly improve care delivery. The need for frequent and vigorous refresher courses, is discussed, along with course content. A system of objective evaluation is presented and the importance of its incorporation into an ongoing data colle ction and quality control system is stressed.