This study addresses operational inefficiencies in the Emergency Department (ED) of a private hospital, focusing on reducing the rate of patients leaving without being seen (LWBS). Value Stream Mapping (VSM) was employed to identify delays and bottlenecks in the patient journey, and a simulation model evaluated potential improvements. Implementing parallel processes, including combined triage with registration and doctor review with payment, reduced total lead time by 14.4%. The Block Diagramming Method (BDM) was applied to optimize the ED layout, repositioning critical rooms and decreasing unnecessary movement by 20%. For long-term improvement, a 1,854 m² ED extension was proposed, with financial feasibility assessed through cost analysis and sensitivity evaluation. The approach provides a practical framework to enhance patient flow, efficiency, and service quality.