Lupus anticoagulant was found in the plasma of 4 patients who presented with late-onset epileptic seizures. Three of the patients had clinical or electroencephalographic evidence of focality. No significant cerebral pathological findings were detected by the computed tomogram except for an old infarction in one case. None of the patients fulfilled the diagnostic criteria for systemic lupus erythematosus. The relationship between late-onset seizures and the presence of lupus anticoagulant is discussed. The possible etiology of an ischemic episode due to hypercoagulability, expressed uniquely by seizures, is suggested.