High- and low-dose methylphenidate administration was evaluated prospectively for 3 elementary school-age children with cerebral palsy, cognitive impairments, and attention-deficit hyperactivity disorder (ADHD) symptoms using single-case, randomized, double-blind, placebo-controlled designs. An observational time sampling protocol was used to directly measure and quantify classroom behavior. Summary level analysis showed that (1) low-dose (0.3 mg/kg/dose) administration was associated with clinically significant (>50%) reductions in stereotyped and disruptive behavior relative to baseline and placebo conditions, (2) high-dose (0.5 mg/kg/dose) administration was associated with exacerbated amounts of stereotyped and disruptive behavior, and (3) no changes were directly observed for task-related behavior at either dose. Results are discussed with respect to previous research with methylphenidate administration and cerebral palsy, and the suggestion is made that further work using larger, randomly selected study samples with complementary measures of behavior and performance appears warranted.