This paper presents a discrete event simulation model to help improving healthcare service provided by an emergency department at a private hospital at Zagazig, Egypt.We construct a patient flow division model by dividing patients according to their severity level. Although patients division and routing have significant evidence in improving health service in terms of waiting times and Length of Stay (LoS), there is a lack in a detailed system evaluation and implementation under this configuration. Based on system observation and health care provider’s interviews, a comprehensive and clear picture of the system has been drawn along with a conceptual model showing different patient flows through the studied system. A discrete event simulation model of the Emergency Department is built using collected data. Different operational scenarios were tested against the baseline scenario to study the impact of patient flow division, including different staff capacities and different patient magnitudes. Results indicate that waiting times and length of patient stay can be significantly improved under the proposed system configuration.