Many individuals with Autism Spectrum Disorders (ADS) exhibit behaviors and symptoms associated with Attention Deficit Hyperactivity Disorder (ADHD). Comorbidity of ADHD symptoms in individuals with ASD have generally been reported to be between 30 and 50% although even higher rates (e.g., as high as 78%) have been reported in clinical samples. Individuals with co-occurring ASD and ADHD are more severely impaired than those with no ADHD. They exhibit significant deficits in social processing, adaptive functioning, executive control and motor problems, which cause major challenges with educational achievement, socialization and behavioral management in these children. ADHD symptoms are similar whether occurring alone or comorbid with autism, so children with ASD may benefit from the same systematically tested, evidence-based treatments that have been proven successful in typically developing children with ADHD. Studies have demonstrated the efficacy of methylphenidate treatment of ADHD symptoms in children with ASD, however, the response rates were lower and discontinuation due to adverse effects were higher compared with the non-ASD ADHD population. Two additional medications (i.e., clonidine and atomoxetine) have also reported to be effective in randomized placebo-controlled trials. Atypical antipsychotic agents have been demonstrated to reduce ADHD symptoms in children with ASD, who have co-occurring irritability and agitation. Compared with typically developing children with ADHD, children who have ASD, as in other developmental disabilities seem to have lower effect sizes with these medications and are more sensitive to side effects, including emotionality and agitation. In this presentation, recent studies on treatment of children with ASD comorbid with ADHD will be presented together with our clinical and research experience.