A 69-yr-old woman was admitted to the intensive care unit after cardiac surgery. Immediately after the discontinuation of cardiopulmonary bypass, she had a circulatory arrest. A 13-min open-chest cardiac massage was followed by 70 min of cardiopulmonary bypass. Right hemiplegia and right extensor plantar reflex were noted after the patient awakened. She had been included in a prospective study protocol measuring, before and after surgery, cerebral blood flow with transcranial Doppler (TCD). The data were retrospectively analyzed, and it was established that the TCD had recorded cerebral perfusion defects. This is the first case of acute ischemic stroke after cardiac arrest with retrospective documentation of asymmetrical cerebral blood flow by a systematic postoperative TCD recording.Clinical neurological examination is often of limited value in deeply sedated patients. This case report describes the early diagnosis of an ischemic stroke by using transcranial Doppler after cardiac surgery. Thus, transcranial Doppler could be used systematically for cerebral perfusion monitoring in patients who have undergone major hemodynamic instabilities.