Outcomes research focuses on the end results of medical care. This paper describes the specific domains of outcomes research, namely, clinical effectiveness, quality of care, quality of life, patient satisfaction, cost-effectiveness, and organization of care, which are the primary domains of outcomes research. Specific examples of pediatric emergency medicine applications are provided for each domain. Outcomes research in the clinical specialties of pediatrics, emergency medicine, and emergency medical services is in an early stage of development relative to that of adult medicine. Thus, the intersection of these clinical specialties, pediatric emergency medicine, presents many challenges and opportunities.