A series of 88 patients with completed stroke was selected in which heralding, early and late seizures were distinguished according to their onset. Relationships between CT scan and clinical EEG data are discussed with particular emphasis on possible mechanisms of seizures. Thus, small emboli or haemodynamic factors are stressed in the cases of heralding seizures, metabolic disturbances with cytotoxic effects in early seizures and chronic epileptic focus in late seizures.