There have been relatively few randomized clinical trials of pharmacology for attention-deficit/hyperactivity (ADHD) in children with autism spectrum disorders (ASD). Atomoxetine (ATX) was approved by the FDA in January 2003 for treatment of ADHD, but only 4 studies of this drug have been conducted in children with ASD. Behavioral treatments, such as training parents in the use of behavioral interventions (PMT), are also standard treatments for ADHD in typically developing children. While PMT also has long been used in ASD, it has rarely been studied in combination with psychopharmacologic treatment in this population. This three-pronged, 10-week trial in children with ASD will compare atomoxetine vs. placebo, PMT vs. no-PMT, and combined ATX/PMT vs. PMT alone. This trial has the potential to provide answers regarding optimal treatment (both psychosocial and pharmacological) for a sizeable subgroup of children with ASD who experience symptoms of over activity and inattention.