OBJECTIVES Over the past two decades, the prevalence of autism spectrum disorder (ASD) has increased significantly in the United States (US). This increase in prevalence has been accompanied by a corresponding increase in health care utilization and costs associated with the disorder. The purpose of this study is to describe hospitalization and associated costs among children with ASD in the US. METHODS For the purpose of the study, the 2006 Healthcare Cost and Utilization Project (HCUP) Kids' Inpatient Database (KID) was used. The 2006 KID contains outcome data for ~3.1 million discharges from 3739 community, non-rehabilitation hospitals spread across 38 states. All hospitalizations where the primary diagnosis (ICD-9-CM) code was listed as 299.XX were categorized as autism-related. Descriptive analyses were performed and results were reported by demographic categories. Costs associated with hospitalizations were based on total charges. RESULTS Of the 3,131,324 pediatric discharges listed in 2006 HCUP KID, 1,456 were autism-related. The total charge for these hospitalizations was $56,936,591. The average charge per autism-related hospitalization was $24,042. The average age of children with autism-related hospitalization was 12 years (±4 years), and the average length of stay was 13 days. In terms of demographic distribution, a majority of the children were white (69%) and male (82.3%). Medicaid was listed as the primary payer for roughly half (49%) of the discharges, with private payer including HMO providing for 42.9%. For approximately 57% of the discharges, the DRG listed was for psychoses, with another 42% for organic disturbances and mental retardation. CONCLUSIONS Autism-related hospitalizations result in significant economic impact on the society. Consistent with the prevalence patterns of autism, a majority of hospitalizations occurred among males. Further research is needed to understand the factors associated with hospitalizations among children with ASD.