This study examined changes in the administrative prevalence of autism spectrum disorders (ASD) in Utah children from 2002 to 2008 by record source (school and health), age (four, six, and eight), and special education classification. Prevalence increased 100% with 1 in 77 children aged eight identified with ASD by 2008. Across study years and age groups rates were higher when health and school data were combined with a greater proportion of cases ascertained from health. The proportion of children with both a health ASD diagnosis and a special education autism classification did not significantly change. Most children with an ASD health diagnosis did not have an autism special education classification. Findings highlight the growing health and educational impact of ASD.