The visual evoked responses (VERs) to flash and pattern stimulation were examined in 44 children with migraine and 8 with periodic syndrome at the Birmingham and Midland Eye Hospital, Birmingham, England. Patients younger than 13 years had higher fast wave amplitude and lower fast wave frequency than controls in the same age groups. In older children the fast wave amplitude was higher in those with migraine than in controls but fast wave frequencies were not different. Children with periodic syndrome had similar fast wave amplitudes to the younger children with migraine. The high fast wave frequency with superimposed intermittent high amplitude sharp waves after flash stimulation seen in patients with periodic syndrome are similar to those seen in acephalgic migraine in adults. The finding of similar VERs in migraine and periodic syndrome supports the inclusion of periodic syndrome in the international classification of migraine.