Background: Reducing and standardizing the wait time and increasing and smoothing the efficiency of the work of emergency personnel with team work requires predicting its results before the decision. Objectives: With using the simulation tool in this study, we examined the results of teamwork in the emergency department. Methods: This is an analytical and applied research that was carried out in September and November 2018 in the emergency department of Sina Hospital on 160 patients in three shifts in the morning, evening and night. In order to collect the data, interviews with authorities and the standard form of the Ministry of Health in accordance with the objectives of the study were used. At the end, with ARENA software, team work simulated and its effects, in 3 scenarios, predicted. Results: As other studies patients' entrance rate was in Poisson. By reducing the number of FAST section nurses, not only the total outflow of patients did not decrease, but the staff efficiency of this sector increased by 19%. In the second and third scenarios, it was observed that with team performance between acute sections 2 and CPR with priority of CPR and acute sections 1 and fast nurses, patient outcomes increased, waiting time relatively low increased, patient outcomes and staff efficiency of these sections increased in a balanced way. Conclusion: To achieve the desired indicators, teamwork was evaluated positively, but doing things by Teamwork is one of the most difficult and costly decisions that before making these decisions, it's better to predict the results of it in virtual environments.
