It is not known whether delivering inpatient care earlier to patients boarding in the emergency department (ED) by a hospitalist-led team can decrease length of stay (LOS). To study the association between care provided by a hospital medicine ED Boarder (EDB) service and LOS. Retrospective cross-sectional study (July 1, 2016 to June 30, 2018) conducted at a single, large, urban academic medical center. Patients admitted to general medicine services from the ED were included. EDB patients were defined as those waiting for more than two hours for an inpatient bed. Patients were categorized as covered EDB, noncovered EDB, or nonboarder. The hospital medicine team provided continuous care to covered EDB patients waiting for an inpatient bed. The primary outcome was median hospital LOS defined as the time period from ED arrival to hospital departure. Secondary outcomes included ED LOS and 30-day ED readmission rate. There were 8,776 covered EDB, 5,866 noncovered EDB, and 2,026 nonboarder patients. The EDB service covered 59.9% of eligible patients and 62.9% of total boarding hours. Median hospital LOS was 4.76 (interquartile range [IQR] 2.90-7.22) days for nonboarders, 4.92 (IQR 3.00-8.03) days for covered EDB patients, and 5.11 (IQR 3.16-8.34) days for noncovered EDB (P < .001). Median ED LOS for nonboarders was 5.6 (IQR 4.2-7.5) hours, 20.7 (IQR 15.8-24.9) hours for covered EDB, and 10.1 (IQR 7.9-13.8) hours for noncovered EDB (P < .001). There was no difference in 30-day ED readmission rates. Admitted patients who were not boarders had the shortest LOS. Among boarded patients, coverage by a hospital medicine-led EDB service was associated with a reduced hospital LOS.