In this study, a modular discrete event simulation (computer modeling) has been presented to support process improvements in a hospital's emergency department (ED) to streamline admitted patient flow to inpatient units. Because the ED in this study has less than 10 beds, unnecessary occupation of beds affects the patient wait time dramatically. Additionally, ED overcrowding diminishes the quality of care, increases costs, and decreases employee and patient satisfaction. The modular simulation model evaluated the effectiveness of several recommended workflow improvements, resulting from comprehensive statistical analysis, based on their impact on cycle time and time traps in the process. The results suggested that, to ensure better efficiency and optimal cycle time, all of the suggested workflow improvements should be implemented simultaneously. The model also suggested that achieving customer satisfaction is possible 96.26% of the time with the current resource allocations in the ED.