Visual illusions characterized by distortion of form, size, reciprocal position of objects, movement, or color, labeled as "Alice in Wonderland" syndrome, were discussed in children with infectious mononucleosis, as well as in other clinical conditions, such as migraine, epilepsy, use of certain hallucinogenic drugs, etc. The purpose of our study was to investigate for the first time visual evoked potential results in children with "Alice in Wonderland" syndrome associated with infectious mononucleosis. Five children with "Alice in Wonderland" syndrome associated with infectious mononucleosis underwent visual evoked potential studies during and after their clinical symptoms. Visual evoked potential results during the disease demonstrated statistically significant high amplitudes of P100-N145 in all children compared to the control group. A few weeks later, repeated studies after the resolution of the complaints were normal. Since the same findings can be observed in patients with migraine, we postulate that a common pathophysiologic underlying abnormality, which can cause transient focal decreased cerebral perfusion, could be involved in the disease process of these two conditions.