Autistic spectrum disorder (ASD) is a lifelong developmental disorder characterized by impairment in socialization and communication. Neuroimaging research has shown abnormalities in the frontal lobes, limbic systems, and cerebella of individuals with ASD. Recently, abnormal developmental trajectories of brain growth have been reported, with increases in brain volume (in both gray and white matter) seen in younger rather than older individuals with this disorder. Despite 30 years of research, a reliable marker for ASD has not been identified. Therefore, routine neuroimaging for individuals with ASD is not recommended.