The prehospital time delay in acute health problem still is a problem in most low- and middle-income countries, like Iran. It often is possible to minimize adverse consequences by promptly providing effective prehospital services

This study was designed to compare the response time interval occurring during the prehospital care process in Tehran during the last decade.

A retrospective, comparative study was designed, and the mean response time intervals in relation to prehospital care were identified from September 1999 until September 2000 were compared with data from September 2009 until September 2010. Data were collected from Tehran emergency medical services (EMS) center registries.

The EMS center of Tehran dispatched 213 ambulances every day in 1999–2000 compared with 1,200 in 2009–2010. During the 2009–2010 period, the mean response time for city locations was 14.18(+ /−4) minutes, compared with 1999–2000 the mean response time for city location was 16(+ /− 8). The mean response time from the time period of 1999–2000 also was longer than for 2009–2010 (14.18 vs. 16.58 minutes).

Despite the prominent increase in the number of ambulance dispatching everyday, the mean response time in Tehran decreased during last decade. This improvement can be due to the improvement of the prehospital system in Tehran, including the number of: ambulances, trained staff, EMS stations, etc. However, it still is far from a national standard (eight minutes for city).