Migraine is a chronic disorder. Visual symptoms and hypersensitivity to light stimuli are common. The aim of this study is the analysis of visual system in migraineurs by visual evoked potentials (VEP). We studied 53 migraineurs (21 with prophylactic migraine treatment and 32 without preventive therapy) and 20 healthy control subjects. We found lower P100 latencies in migraineurs without therapy compared to controls. In treated patients, P100 latencies showed the same trend seen in the control group. We speculate a different responsiveness of the visual system in migraineurs probably due to a dysmodulation of sensor input leading to facilitation of visual processing.