[영문]Background: Emergency departments (EDs) function at the interface of complex systems of the hospital and play a critical role in safety net systems. Adequate level of nurse staffing is crucial in meeting patients' needs and assuring their safety in EDs.Purposes: This study examined the impact of nurse staffing on ED market shares.Methodology/Approach: Data were collected from 122 hospitals operating nationally designated emergency medical centers. Multiple regression analyses were conducted to explain ED market share with the nurse staffing level.Findings: After controlling for hospital and regional characteristics, nurse staffing level significantly influenced market shares. Specifically, increasing one level from the baseline nurse staffing resulted in 29% higher ED market share.Practice Implications: Higher nurse staffing level is sensitively linked to the higher market share in emergency care services. These findings provide an initiative for hospital managers and nurse administrators to recruit and retain more nurses for pursuing higher nurse staffing. Furthermore, continuous effort should be made to develop a high standard of establishing and maintaining an adequate level of nurse staffing