Attention-deficit/hyperactivity disorder (ADHD) affects 9-12% of individuals with intellectual disability (ID). Although psychostimulant medication is often the primary treatment modality, little is known regarding the effects of such agents on social interactions and play in this population. Additionally, the role of ADHD symptoms in social and play deficits (beyond that accounted for by ID alone) is not well understood. The first aim of this study was to examine differences in play skills between children with ADHD and ID and non-ADHD/ID controls. The second aim was to determine what, if any, changes in social/play behavior would occur with the use of the stimulant, methylphenidate, among the participants with ADHD/ID. It was hypothesized that the ADHD/ID group would display significantly greater activity level, "rough" play, and more aggression than matched controls. Additionally, it was hypothesized that these deficits would evidence statistically significant improvement with pharmacologic treatment. This study replicates prior work conducted by the authors. (Contains 3 tables.)