Introduction: With a dramatic increase in costly mass casualty incidents over the past few decades, disaster planning and preparedness now represent a prominent part of health care policy and practice. Administration of computer technologies, including computerized simulation techniques, in hospitals can improve management of future incidents.

Materials and Methods: In this research, we used SIMAN/ARENA software of disaster management in one of the teaching hospitals of Tehran University of Medical Sciences. Data about the patients&apos need for specific surgeries, possibility of re-operation, length of operations and necessary equipment’s including number of operating rooms and staff, imaging facilities and treatment stations in emergency department were collected. Two teams took part in this program: a simulation team and the hospital staff team. Both teams were trained before taking part in this study.

Results: With the help of simulation system, the simulation team created various preplanned “events” and simulated in and out hospital situations. Hospital staff team reacted to these situations and was able to recognize and solve various problems in different critical points in hospital by using different tactical means.

Conclusion: Simulation technique used in this limited scale drill was useful in evaluating and improving preparedness of hospitals for managing a multi-casualty incident. The current system can be used in all hospitals in Iran to improve preparedness for receiving victims of a multi-casualty incident.