Autism is a pervasive developmental disorder with onset in infancy or childhood. Research has identified infant/toddler characteristics that should suggest autism to pediatric primary care providers. Many autistic children can be referred for diagnosis as young toddlers if social, perceptual, and language delays are considered significant. Early diagnosis of children with autism allows intervention, which helps the child modulate disturbing sensory stimuli and seeks to meet his/her unique social and communication needs. This article describes the disorder and its management and offers guidelines for recognizing young children who would benefit from further comprehensive neurobiologic evaluations by developmental specialists.