Introduction: There are 161 emergency medicine residency programs in the United States, many of which have medical students rotating through the emergency department (ED). Medical students are typically supervised by senior residents or attendings while working a regular shift. Many believe that having students see and present patients prolongs length of stay (LOS), as care can be delayed. Our institution implemented a unique method of educating medical students while in the ED with the creation of a teaching service, whose primary goal is education in the setting of clinical care. The objective of this study was to explore the effect of the teaching service on efficiency by describing LOS and number of patients seen on shifts with and without a teaching service. Methods: This was a retrospective chart review performed over a 12-month period of visits to an urban academic ED. We collected data on all patients placed in a room between 14:00 and 19:59, as these were the hours that the teaching shift worked in the department. We categorized shifts as 1) a teaching service with students (TWS); 2) a teaching service without students (TWOS); and 3) no teaching service (NTS). LOS and median number of patients seen on days with a teaching service, both with and without students (TWS and TWOS), was compared to LOS on days without a teaching service (NTS).Results: The median LOS on shifts with a dedicated teaching service without students (TWOS) was 206 minutes, while the median LOS on shifts with a teaching service with students (TWS) was 220 minutes. In comparison, the median LOS on shifts when no teaching service was present (NTS) was 202.5 minutes. The median number of patients seen on shifts with the teaching service with students (TWS) was 44, identical to the number seen on shifts when the teaching service was present without students (TWOS). When the teaching service was absent (NTS), the median number of patients seen was 40. Conclusion: A teaching service in the ED is a novel educational model for medical student and resident instruction that increases total ED patient throughput and has only a modest effect on increased median length of stay for patients. [West J Emerg Med. 2014;15(2):165–169.]