The present study examined the degree to which methylphenidate (MPH) normalized the classroom behavior and academic functioning of 31 children with attention deficit disorder (ADD). Subjects with ADD participated in a double-blind, placebo-controlled trial in which children received each of four doses (5, 10, 15, and 20 mg) of MPH and a placebo following baseline measures. Children with ADD were compared with a group of 25 normal control children on teacher ratings of social conduct, direct observations of on-task behavior, and academic efficiency. At a group level of analysis, MPH exerted a significant effect on classroom measures of attention and academic efficiency to a point where they were no longer statistically deviant from scores obtained by normal control children. Nevertheless, when examined at the individual level, 25% of the sample failed to show normalized levels of classroom performance, thus implying the need for ancillary school-based interventions.