Stimulus-evoked electrographic patterns are described for 12 neonates, coincident with tactile or painful stimulation. Four newborns had stimulus-evoked electrographic seizures with and without concomitant clinical seizure behaviors. Eight neonates had generalized or focal stimulus-evoked discharges, with or without coincident movements, which did not evolve into electrographic seizures. Nine infants were less than 36 weeks estimated gestational age at the time stimulus-evoked discharges were noted. Eleven neonates were comatose or phamacologically paralyzed at the time the stimulus-evoked patterns were initially noted. All neonates had moderate or severe interictal EEG background abnormalities at the time these patterns were observed. All patients had brain lesions documented by either cranial imaging or neuropathological examinations. Eleven patients died or have significant neurological handicaps. These phenomena represent an abnormal form of cortical reactivity to sensory stimuli in the developing brain. Most neonates with these patterns have significant diffuse or multifocal damage to the neocortex.