Seventy-eight patients with post-stroke seizures were studied retrospectively to determine the clinical, EEG and CT features of these seizures and their prognosis. There were 57 cerebral infarctions and 21 hemorrhages. Twenty-eight (36%) initial seizures occurred within one month after the stroke (0-24 hours in 19 cases) and were classified as early-onset seizures. Fifty (64%) initial seizures occurred more than 3 months after the stroke (3-12 months in 33 cases) and were classified as late-onset seizures. Compared with a population of 1938 strokes admitted during the same period, the proportion of patients with alcohol abuse, infarction in the anterior cerebral artery territory, watershed infarcts and lobar haemorrhages was significantly greater in our series. The proportion did not vary with the nature of the stroke (infarction or hemorrhage), except for early onset seizures in which the proportion of hemorrhages was significantly greater. Nor did it vary with the cause of hemispheric infarctions (cardioembolism or atherothrombosis or others). Ninety-five percent of the lesions affected the cerebral cortex or the subcortical white matter or both. Of all 78 initial seizures, 64% were partial motor (simple or secondarily generalized); 32% were primarily generalized, and 4% were partial not motor; status epilepticus was seen in 14% of the cases. An initial EEG, performed in 76 patients was normal in 7. Among the remaining 69 patients EEG showed focal or diffuse slowing down in 63% and epileptic features in 37% (including 10 cases of PLEDs). Early post-seizure EEG and repeated recordings significantly increased the specificity of EEG.(ABSTRACT TRUNCATED AT 250 WORDS)