We studied 11 epileptic children aged 7 to 14 years with quantitative electroencephalographic (EEG) and neuropsychological tests, both on and off the barbiturate anticonvulsants phenobarbital and mephobarbital, comparing them to 13 controls matched for age and IQ who received testing at similar intervals. Neuropsychological tests employed were the Wechsler Intelligence Scale for Children-Revised (WISC-R), Bender-Gestalt, controlled oral word association test (COWAT), selected subtests of the Wechsler Memory Scale-Revised, Purdue Peg Board, Stroop Test, Trail Making Test, Wide Range Achievement Test-Revised, and Achenbach Behavior Rating Scale. There was no difference between on- and off-drug quantitative EEG in percentage power of any frequency band between 0.6 and 32 Hz. Neuropsychological data from all 11 subjects were analyzed with a two-factor analysis of variance with repeated measures on the time factor. The only difference from controls was on the Stroop Test. Parents reported clear behavioral changes in 6 of 11 subjects, but in 4 of these children the behavioral changes were sufficiently mild that parents chose to continue the barbiturate anticonvulsants: irritability, oppositional attitude, and overactivity were described. Mephobarbital was reported by parents to cause less severe problems than phenobarbital in subjects who had taken both barbiturate anticonvulsants. Barbiturate anticonvulsants have no effect on quantitative EEG and limited effects on neuropsychological tests in school-aged children.