Although many of the prominent symptoms of minimal brain dysfunction (MBD) subside during pubescence, adolescents who had MBD during childhood may have persistent neuropsychological dysfunctions. The authors studied the auditory average cortical evoked potentials and behavioral responses of 9 formerly hyperactive adolescent boys and 9 matched control subjects who performed a selective attention task. Experimental subjects showed indications of impairment on both electrophysiological and behavioral measures of selective attention. Although the findings are consistent with a neurodevelopmental lag interpretation of MBD, they may also imply a persistent dysfunction related to the frontal association cortex.