The Santa Cruz County 9-1-1 emergency response system was taxed severely with over 1,000 calls during the first seven hours following the Loma Prieta earthquake. It remained functional and responsive, making 229 ambulance runs in the 72-hour period following the earthquake. Initially, the demand was very high compared to normal, but decreased to slightly greater than normal levels during the second day. A fewer than normal number of advanced life support transports were required, and the number of vehicular accident cases were fewer than normal following the earthquake. The 9-1-1 center adopted an abbreviated procedure and only attempted to determine if the call was a medical emergency and the location for dispatch. During the initial emergency period, there were an unusually low proportion of transports and an unusually high number of cases in which the patient was not located. The medical system in Santa Cruz County was able to accommodate the injury load: the health care system was extensive; its three community hospitals were not damaged severely; and there was light demand.Based on this experience, a revised 9-1-1 emergency medical services (EMS) procedure is recommended for disaster periods: 1) the dispatcher inquires whether the patient can be transported by other means; 2) the caller is asked to explain the need for an ambulance in order to assign a priority to the request; and 3) the caller is asked to cancel the call if there no longer is a need. This procedure is expected to improve disaster management of limited ambulance resources during and following a disaster, while maintaining rapid call processing.