Nowadays, healthcare systems services have become a serious concern for many countries across the world. Due to its complexity and Variability the Emergency Department (ED) is considered the most critical unit of the hospital and the healthcare systems in general. Increasing the patient satisfaction, reducing as much as possible the patient's waiting time and the patient's length of stay, and optimizing the resources utilization are the overriding preoccupation for any ED manager. To support the performance enhancement in the ED, simulation studies have profusely been involved. In this paper the authors describe a decision support system based on the combination of a simulation and a temporal knowledge extraction model for the operation improvement of the emergency department in the public hospital Lakhdar Bouzidi in Bordj Bou Arreridj (Algeria). Their methodology points out how agent-based modeling simulation can benefit from data mining analysis methods to provide a powerful decision support system that can help managers to improve the functioning of the ED.