Autism spectrum disorders are being diagnosed with increasing frequency. The likelihood that a primary care provider will see a patient with autism spectrum disorder in their clinic is high. In this article, current diagnostic criteria and expected changes in DSM criteria, as well as prevalence rates and epidemiologic studies are reviewed. Recommendations for screening, including early warning signs, and best practices for diagnosis are discussed. Comprehensive evidence based intervention for ASD as well as the findings of the National Standards Project are reviewed. Medication management is also described, as are the roles of other treating professionals.