Stroke occurs as a result of ischemic injury to neural tissue, as a result of cardiogenic or artery to artery embolism or intracranial arterial thrombosis. The traditional vascular risk factors, namely hypertension, diabetes mellitus, tobacco smoking, family history and hyperlipidemia as well as atrial fibrillation are major determinants of stroke risk. Obstructive sleep apnea (OSA) has been shown to be a risk factor for hypertension and,although the association is less strong, atherosclerotic heart disease.There is a high prevalence of OSA amongst stroke patients, on the order of 60 to 70%, which is tenfold higher than in the general healthy population. Recently, it has been shown that, in stroke patients undergoing inpatient rehabilitation,the presence of OSA predicts both a poor functional outcome and greater length of hospitalization in the rehabilitation unit, even after adjustment for stroke severity.