To identify characteristics of adolescents who access health care in a children's hospital emergency department (ED) compared with a general ED. We performed a retrospective comparative study of an urban children's ED and the adjacent general ED. Participants included randomly selected ED visits of adolescents aged 15 to 19 years who presented during a 1-year period. Demographic data, triage category, chief complaint, and comorbid conditions were collected and analyzed by site of care. Ten percent of visits to each location was reviewed. Adolescents in the general ED were more often female (72% vs 60%), uninsured (32% vs 12%), and presented with abdominal pain (46% vs 17%). Adolescents in the children's ED more frequently identified a primary care provider (94% vs 58%) and were triaged as non-urgent (40% vs 22%). In the children's ED, more complaints were injury-related (30% vs 19%). The prevalence of complaints related to violence or chronic diseases did not vary. Through logistic regression analysis, adolescents using the general ED were more likely to be older (odds ratio [OR], 4.1, 95% confidence interval [CI], 3.2-5.3) and to complain of abdominal pain (OR, 5.0; 95% CI, 2.8-8.8); those using the children's ED were more likely to present with a non-urgent complaint (OR, 2.7; 95% CI, 1.5-4.9) and identify a primary care provider (OR, 16.6; 95% CI, 17.6-36.4). When a children's and general ED are in close proximity, there are unique characteristics of the adolescents at each site. Understanding the differences can assist clinicians to provide care tailored to meet the needs of each group.