Twenty-nine patients with migraine were examined by CT-Scans. Ten of these had abnormalities on the scans which consisted of cerebral parenchymal low densitometric areas, ventricular enlargements and conical atrophy. The cerebral parenchymal low densitometer zones tended to disappear on repeat scanning. Four cases in the series had hemiparetic migraine and all showed abnormalities on CT-scans. The incidence of complicated migraine was higher in patients who showed abnormalities on the scans than in those with normal scans. It is suggested that the parenchymal low density areas on CT-scans are the result of cerebral edema, but that repeated insults might lead to permanent changes in brain parenchyma which might be recognizable as cortical atrophy and ventricular enlargement.