OBJECTIVE Patients in an urban environment may utilize Emergency Departments (ED) differently than patients in a suburban environment. Previous research has demonstrated that significant differences exist among the percentage of patients admitted dependent upon their mode of arrival to the ED. The purpose of this study was to further investigate the admission rates of suburban versus urban hospitals based on patient mode of arrival. The modes of arrival that were investigated include walk-in patients, Basic Life Support (BLS) transports, and Advanced Life Support (ALS) transports. METHODS We used a retrospective cohort design. Data were collected from the ED's of a suburban Level I trauma center and an urban Level IV trauma center in the same health care system. These hospitals are located 14 miles apart and see a cumulative annual volume of approximately 150,000 ED patients. The State's prehospital system is a two tier structure with BLS and ALS. Patients presenting to the ED from the first Wednesday of alternating months (January, March, May, July, September, and November) in 2007 were reviewed. Medical record numbers and ED patient tracking systems were used to determine patient disposition. Confidence intervals were determined using the Agresti-Coull binomial method and p-values were determined using Pearson's chi-squared. RESULTS A total of 2,438 ED encounters were reviewed. See Table for results. CONCLUSIONS Walk-in patients at the suburban ED required admission twice as often as in the urban ED. No significant differences in suburban ED admission rates between BLS or ALS transports existed when compared to the urban ED. This suggests that urban patients are more likely to seek non emergent care from an ED than their suburban counterparts. Patients activating emergency medical services had similar rates in these suburban and urban hospitals.