Objective: To test that methylphenidate combined with intensive multimodal psychosocial intervention, which includes social skills training, significantly enhances social functioning in children with attention-deficit/hyperactivity disorder (ADHD) compared with methylphenidate alone and methylphenidate plus nonspecific psychosocial treatment (attention control). Method: One hundred three children with ADHD (ages 7-9), free of conduct and learning disorders, who responded to short-term methylphenidate were randomized for 2 years to receive (1) methylphenidate alone, (2) methylphenidate plus multimodal psychosocial treatment that included social skills training, or (3) methylphenidate plus attention control treatment. Assessments included parent, child, and teacher ratings of social function and direct school observations in gym. Results: No advantage was found on any measure of social functioning for the combination treatment over methylphenidate alone or methylphenidate plus attention control. Significant improvement occurred across all treatments and continued over 2 years. Conclusions: In young children with ADHD, there is no support for clinic-based social skills training as part of a long-term psychosocial intervention to improve social behavior. Significant benefits from methylphenidate were stable over 2 years.