This study assessed the safety and efficacy of methylphenidate in children with seizures and attention-deficit disorder. Ten children, aged 6 years 10 months to 10 years 10 months, without seizures while receiving a single antiepileptic drug, were evaluated in a double-blind medication-placebo crossover study with methylphenidate hydrochloride was administered at 0.3 mg/kg per dose and given at 8 AM and 12 PM on school days only. The use of methylphenidate was associated with statistically significant improvements on the Conners' Teacher Rating Scale and on the Finger Tapping Task and with trends toward improvement on the Matching Familiar Figures Test and Discriminant Reaction Time tests. No child had seizures during the study period nor subsequently for those who continued receiving psychostimulants. There were no significant changes of epileptiform features or back-ground activity on electroencephalograms and no alterations in antiepileptic drug levels. Methylphenidate may be a safe and effective treatment for certain children with seizures and concurrent attention-deficit disorder.