• The short-term, dose-response effects of methylphenidate hydrochloride were evaluated on academic and social classroom measures in 29 children with attention deficit disorder. In a double-blind, cross-over design with order randomized, children received a placebo for two weeks and three doses of methylphenidate hydrochloride (0.15 mg/kg, 0.3 mg/kg, and 0.6 mg/kg) for one week each. Dependent measures included the output and accuracy of performance in grade-appropriate reading comprehension workbooks and arithmetic problems, spelling word acquisition, and observations of disruptive and on-task behavior. Beneficial drug effects and linear dose-response curves on all dependent measures were found. The results suggest that beneficial methylphenidate effects on classroom behavior may be accompanied by enhanced academic achievement in some hyperactive children.