Stroke is one of the leading causes of mortality, and several risk factors have been identified that may be modified to ameliorate this risk. Recently, obstructive sleep apnea (OSA) has been implicated as a possible additional risk factor for stroke. OSA is a common disorder characterized by repeated upper airway collapse during sleep leading to multiple physiologic abnormalities. Several recent studies suggest that OSA is an independent risk factor for stroke. This independent association is likely due to derangement of normal sleep physiology and the attendant consequences to autonomic, vascular endothelial, and thrombotic/fibrinolytic dysfunction leading to the development of atherosclerosis. Additionally, OSAs contribution to the development of known risk factors for stroke such as hypertension and atrial fibrillation may also predispose a patient to develop cerebrovascular disease. Patients presenting with stroke who are also diagnosed with OSA have a worse prognosis than those without OSA. Therapy with continuous positive airway pressure (CPAP), the treatment of choice for most patients with OSA, appears to be beneficial, but achieving compliance in patients post-stroke is difficult.