Respiratory disturbance during sleep, in its most common form, obstructive sleep apnea, is a prevalent condition in the general population. During the past several years, researchers have investigated a possible link between obstructive sleep apnea and hypertension. This article discusses the available epidemiologic and clinical evidence supporting this link. The possible mechanisms leading to the development of hypertension in patients with obstructive sleep apnea will also be discussed, as well as the effects of therapeutic interventions on arterial blood pressure. Last, the clinical importance of such interaction, which may lead to excessive cardiovascular morbidity and mortality, will be addressed.