Autism spectrum disorder (ASD) is the most common and fastest-growing developmental disability in the United States, affecting approximately one in 54 children nationwide. Early intervention for ASD produces the best outcomes-and developmental surveillance and screening are prerequisites to intervention. Although screening has been strongly recommended for two decades, the majority of U.S. children are not screened for ASD. Here, the authors discuss ASD epidemiology, screening, and diagnosis, as well as appropriate early actions nurses can take when ASD is suspected.