The characteristics of SEP cortical components were studied in 40 children with focal idiopathic epilepsies of childhood. Twenty children had focal idiopathic epilepsies and evoked spikes (FIE-ES) on the EEG and 20 had benign focal epilepsy of childhood with centrotemporal spikes (CTE) but without evoked spikes (ES). These data were compared with those of a control group of 20 normal children. N35 high-amplitude component was more frequent in the CTE group than in the control group (p<0.001). P98 showed high amplitude in 50% of the children of FIE-ES group, and in none of the CTE and control groups (p<0.001). The P98 high amplitude component was more common in the FIE-ES group than in the other groups, and so was the N35 high amplitude component in the CTE group. Lateralization of high-amplitude components of N35 in the CTE group and of P98 in FIE group was not correlated with lateralization of epileptiform activity and evoked spikes. Based on our findings, there are SEPs cortical component differences in childhood focal idiopathic epilepsies according to occurrence or absence of ES.363194198