Emergency Department (ED) is the center of the hospital management’s efforts. It constitutes a complex system with limited resources and random demands. The goal of this thesis is to optimize healthcare emergency departments the number of the human and material resources. Our focus is particularly on medical staff (physicians and nurses) and beds in emergency department. The goal is to minimize the waiting time of patients. We consider several patients’ queues and uncertain events. To solve this problem, we propose exact methods and heuristics approaches.