BACKGROUND: Young adults have a high prevalence of many preventable diseases and frequently lack a usual source of ambulatory care, yet little is known about their use of the emergency department. OBJECTIVE: To characterize care provided to young adults in the emergency department. DESIGN, SETTING, AND PARTICIPANTS: Cross-sectional analysis of visits from young adults age 20 to 29 presenting to emergency departments (N=17,048) and outpatient departments (N=14,443) in the National Hospital Ambulatory Medical Care Survey and National Ambulatory Medical Care Survey. MAIN MEASURES: Visits to the emergency department compared to ambulatory offices. RESULTS: Emergency department care accounts for 21.6% of all health care visits from young adults, more than children/adolescents (12.6%; P<0.001) or patients 30 years and over (8.3%; P<0.001). Visits from young adults were considerably more likely to occur in the emergency department for both injury-related and noninjury-related reasons compared to children/adolescents (P<0.001) or older adults (P<0.001). Visits from black young adults were more likely than whites to occur in the emergency department (36.2% vs.19.2%; P< 0.001) rather than outpatient offices. The proportion of care delivered to black young adults in the emergency department increased between 1996 and 2006 (25.9% to 38.5%; P=0.001 for trend). In 2006, nearly half (48.5%) of all health care provided to young black men was delivered through emergency departments. The urgency of young adult emergency visits was less than other age groups and few (4.7%) resulted in hospital admission. CONCLUSIONS: A considerable amount of care provided to young adults is delivered through emergency departments. Trends suggest that young adults are increasingly relying on emergency departments for health care, while being seen for less urgent indications.KEY WORDS: emergency care; ambulatory care; young adults.