Autism and autism spectrum disorder (ASD) are a group of severe developmental disorders that are characterized by 3 core sets of developmental abnormalities: impairment of social interaction, verbal and nonverbal communication, and restricted, repetitive patterns of behavior. The disorder is far more common than previously thought. There is no cure for autism but it is apparent that early detection followed by early intervention is likely to provide the best chance of long-term beneficial outcome in this condition. Unfortunately, until recently, there had been no validated method of comprehensive early detection of ASD, nor a tool with adequate sensitivity and specificity to be recommended for universal screening of preschool children with ASD. We describe a model of comprehensive early detection and diagnosis of ASD that is achieved by using the resources of primary care workers and a multidisciplinary team with skill and experience in assessing developmental problems in young children and specific expertise in ASD. Both early detection and diagnosis may be carried out by this team in collaboration with parents and primary care professionals and can result in high rates of detection and diagnosis of ASD.