A critical review is presented of the reported data allegedly indicative of a relationship between migraine and epilepsy. These data are considered under five major headings: genetic, epidemiological, clinical, electro-neurophysiological and neurochemical. Genetic data fail to reveal a basis on which to argue for a common single genetic trait. Both disorders pathogenetically are the result of polygenic predisposition and environmental factors. Epidemiological data such as are left after strict analysis indicate that coincidental concurrence of the two disorders show superficial resemblances and fundamental differences. The neurochemical basis of both disorders appears to diverge widely. Electrophysiological data support the conclusion arrived at in the genetic discussion. It is concluded that migraine and epilepsy are not linked in any fundamental function.