Background: Trauma still stands atop of the list of emergencies. Transfer of these patients via Emergency Medical Services (EMS) dispatch is critical with regard to importance of timing. This aspect has achieved greater importance due to population increase and telephone triage . Objectives: We aimed to decrease unnecessary Emergency Medical Services (EMS) missions via a computer program designed for an algorithmic approach for trauma care by nurses involved in EMS, to help them evaluate the case more accurately. We named our program "Trauma Dispatch Algorithm". Materials and Methods: First, the most common chief complaints regarding traumatic events were chosen from searching all the calls in December 2008 recorded in Tehran, Iran’s EMS center; and then an algorithm approach was written for them. These algorithms were revised by three traumatologists and emergency medicine specialists, after their approval the algorithms were evaluated by EMS dispatch center for their practicality. Finally all data were turned into computer software. The program was used at the Tehran EMS center; 100 recorded calls assessed with each system were selected randomly. They were evaluated by another traumatologist whether it was necessary to send a team to the site or not. Results: The age average was 26 years in both groups. The "trauma dispatch algorithm" was significantly effective in reducing the unnecessary missions of EMS by 16% (from 42% to 26%) (P = 0.005). Conclusions: This program was effective in reducing unnecessary missions. We propose the usage of this system in all EMS centers.