A survey of emergency department visits was conducted over a 56-week period between November 1980 and November 1981. Inappropriate ambulance use and unmet ambulance need were compared between two cities (one large and one small) with paramedic ambulance services and two cities (one large and one small) with nonparamedic ambulance services. A total of 6,405 visits was evaluated, resulting in overall rates of inappropriate use and unmet need of 42% and 58%, respectively. When paramedic ambulance services were compared to nonparamedic services, the results indicated less inappropriate use in cities with paramedic services (34% vs 49%, P less than .001) as well as less unmet need in cities with paramedic services (48% vs 67%, P less than .001). These results remain consistent within most sample subgroups based on age, sex, time of arrival at ED, and disposition, except that no differences were found for small cities or for patients 50 years and older. The results indicate that paramedic ambulance systems are beneficial to the general population of emergency department users.