Using pattern reversal stimuli, visual evoked potentials (VEP) were measured between attacks in 40 (6 classic and 34 common) migraine sufferers, and in 20 control subjects. While there were no statistically significant differences between the groups in mean P wave latency or in mean P wave amplitude, there were some intriguing individual findings in some of the migraine patients. Nine had P wave latencies more than 2 SD above the control mean; 6 had more than 2 SD increases above control in P wave amplitude; 3 had simultaneous increases in both latencies and amplitudes. In almost all the cases with these unusual values, the tracing had been done close in time to a migraine attack.