Objective To examine differences between general and pediatric emergency departments in adherence to AAP bronchiolitis management guidelines. Methods We conducted a nationally representative study of ED visits by infants <24 months of age with bronchiolitis from 2002-2011 using the National Hospital Ambulatory Medical Care Survey. Diagnostic testing (complete blood counts, radiographs) and medication use (albuterol, corticosteroids, antibiotics and intravenous fluids) in GEDs were compared with PEDs before and after 2006 AAP guideline publication. Weighted percentages were compared and logistic regression evaluated the association between ED type and resource use. Results Of over 2.5 million ED visits for bronchiolitis from 2002-2011, 77.3% occurred in GEDs. GEDs were more likely to use radiography (62.7% vs. 42.1%, aOR 2.4 [95%CI 1.4,4.1]), antibiotics (41.3% vs. 18.8%, aOR 2.8 [1.5,5.2]), and corticosteroids (24.3% vs. 12.5%, aOR 2.1 [1.0,4.5]) compared to PEDs. Compared to pre-guideline, after guideline publication PEDs had a greater decrease in radiography use (-19.7%, 95%CI -39.3,-0.03) compared with GEDs (-12.2%, 95%CI -22.3,-2.1) and PEDs showed a significant decline in corticosteroid use (-12.4%, 95%CI -22.1,-2.8%) whereas GEDs showed no significant decline (-4.6%, 95%CI -13.5, 4.3). Conclusions The majority of ED visits for bronchiolitis in the US occurred in GEDs, yet GEDs had increased use of radiography, corticosteroid, and antibiotics and did not show substantial declines with national guideline publication. Given that national guidelines discourage the use of such tests and treatments in the management of bronchiolitis, efforts are required to decrease ED use of these resources in infants with bronchiolitis, particularly in GEDs.