The authors compare visual evoked responses (VER) elicited at 1, 2,5, 5, 10 and 15 flashes/sec in 213 children aged between 3 and 15 years, distributed in three groups: A, 58 normal children; B, 85 in whom intermitten photic stimulation (IPS) elicits spikes and waves or multiply those spontaneously present; C, 70 with paroxysmal EEG abnormalities insensitive to IPS. The following VER were considered: (i) at 1 flash/sec the morphoplogy of responses, their amplitude, the culmination time of the main deflections, the presence of a post-discharge; (ii) at other flash frequencies, the number of deflections, their culmination times, the possible potentiation of the responses, involving the global amplitude or that of one or several deflections, the possible presence of simplified responses, called ‘undulatory’. These various parameters were studied and compared for all flash frequencies and in two different conditions, eyes open and eyes closed. Statistically significant differences exist between the groups invovlving the response morphology and the presence of a post-discharge in the VER at 1 flash/sec. In the group (B) activated by IPS, the first deflections (N 0, P 1, N 2, P 2) were much more often polyphasic than in the other groups. Likewise, the responses recorded with the eyes closed were followed by a post-discharge in many more children of group B (activating IPS) than of group C and above all of group A. On the other hand, other parameters studied at the various frequencies of IPS were not, when present, significantly different. The authors conclude that, in most cases, the paroxysmal abmormalities elicited in man by IPS are probably not directly related to the functional properties of the visual cortical areas.