Clinical, electroencephalographic, rheoencephalographic and linear cerebral circulation findings were compared for 71 epileptics (group 1), 62 migraine patients (group 2) and 6 patients with epilepsy which had developed in the presence of severe migraine with aura (group 3). One-third of migraine patients, mostly of young age, suffering from migraine with aura and basilar migraine had such consciousness disorders as stupefaction and syncopes. EEG changes in migraine patients were considered nonspecific, paroxysmal spike activity arose only in addition of epileptic seizures. Cerebral blood flow measured by radionuclide tracing in migraine-free interval tended to speeding up, while in groups 1 and 3 hemocirculation was slow. Epileptogenic provocation in group 1 patients accelerated cerebral blood flow on the side of the focus, but decelerated it in group 3. The authors hold that the nature of migraine and epilepsy is different. By disintegration of cerebrovascular regulation and vascular supply of the neuron, migraine may promote secondary epileptogenesis.