This paper addresses the problem of potential overcrowding by patients in the emergency unit of the Asir governmental hospital located in Abha city, Saudi Arabia. This issue affects the patient waiting time, the level of service provided, the quality of service, and the level of pressure on the medical staff; thus, waiting lines are formed, for various reasons.  The main objective of this paper is to reduce the waiting time of patients and to increase the efficiency of the emergency unit. This paper presents an attempt to apply queuing theory to an emergency unit; the calculations made in this paper are based upon actual observed data collected from the emergency unit in the Asir governmental hospital to identify the appropriate distributions for access and service times. The research serves as the basis for a computer simulation model to accurately represent the current reality of the system, to assist decision-makers in overcoming the wait time problem to reduce patient waiting time to zero minutes. Actual data and simulation results revealed the waiting time and number of patients in the queue decreased upon the application of queueing theory.