The earliest sign of autism in children is the delayed attainment of social skill milestones, including joint attention, social orienting, and pretend play. Language impairment is a common, but less specific, sign of autism. Repetitive behaviors and restricted interests may not be noted until after social skill and communication impairments are exhibited. Physicians should perform developmental surveillance at all well-child visits, and the American Academy of Pediatrics recommends administering an autism-specific screening tool at the 18- and 24-month visits. A referral for comprehensive diagnostic evaluation is appropriate if concerns arise from surveillance, screening, or parental observations. The goals of long-term management are to maximize functional independence and community engagement, minimize maladaptive behaviors, and provide family and caregiver support. Physicians play an important role in coordinating care through an interdisciplinary team; referring families for specialized services; and treating children's associated conditions, including sleep disturbances, gastrointestinal problems, anxiety, and hyperactivity. Autism is a lifelong condition, but early recognition, diagnosis, and treatment can improve the prognosis, whereas associated medical conditions, psychiatric conditions, and intellectual disability can worsen the prognosis.