The long-term objective of the proposed project is to reduce injury morbidity and mortality in children with autism spectrum disorders (ASD). The specific aims are to: 1) examine the time trends of injuries treated in emergency departments (EDs) and hospitals among children with ASD aged 0?20 years; 2) characterize the epidemiologic patterns of injuries treated in EDs and hospitals among children with ASD according to age, sex, injury mechanism, intent and severity; and 3) assess the excess risks of injuries treated in EDs and hospitals associated with ASD. The estimated prevalence of ASD continues to rise. Surveillance data in the United States indicate that one in 59 children aged 8 years in 2014 met the diagnostic criteria for ASD and that one in 40 children aged 3 to 17 years had parent-reported ASD diagnosis. Injury has long been recognized as a major cause of morbidity and mortality in children in the United States, resulting in approximately 18,000 deaths with over 9 million emergency department visits and more than 200,000 hospitalizations among children younger than 20 years of age annually. Recent studies indicate that children with ASD may be at exceptionally heightened risk of injury mortality and certain types of injury morbidity, likely due to impairments in social, cognitive and behavioral functioning and common comorbid conditions such as attention deficit hyperactivity disorder and intellectual disability. Research on injury in children with ASD is inadequate and often limited by small sample sizes and self-reported data. Building on our recent work on injury mortality in children with ASD and injuries in preschool age children with ASD, the proposed project aims to close an important research gap by examining the time trends, epidemiologic patterns and excess risks of injuries treated in EDs and hospitals in children with ASD under 21 years of age based on nationally representative samples. We will use the Nationwide Emergency Department Sample for years 2009?2019 and the triennial Kids? Inpatient Database from 1997 to 2019 to create datasets for pediatric ED patients with a diagnosis of ASD (n ? 300,000) and for pediatric inpatients with a diagnosis of ASD (n ? 70,000). We will examine the time trends, epidemiologic patterns and excess risks of injuries treated in EDs and hospitals among children with ASD according to injury mechanism, intent, severity, demographic characteristics, comorbid conditions, and geographic regions compared to the general pediatric patient population. Results from the proposed project will inform preventive strategies and facilitate the development of effective interventions to reduce injuries in children with ASD.