We studied polysomnographic recordings using an Oxford Medilog 9000 System in 18 patients with ischemic stroke in the middle cerebral artery territory. All patients underwent neurologic examination and brain CT scan within 5 h after the onset of symptoms. Polysomnographic recordings were started immediately thereafter and went on for three nights. Clinical and polysomnographic follow-up were performed 3 weeks after admission. The number and duration of REM phases were significantly reduced in the acute phase. This reduction correlated with the severity of neurological deficit at outcome and with the anatomical site of the lesion on CT scan. Our data provide evidence that polysomnographic recording is useful to detect symptoms of patients with different clinical outcomes during the acute phase of ischemic stroke.