Obstructive sleep apnea is an increasingly common disorder and it is a novel cardiovascular disease risk factor. Repetitive apneas and hypopneas during sleep are accompanied by hypoxia, increased sympathetic activity and frequent arousals. Sleep apnea has clearly been demonstrated to be an independent risk factor for development of hypertension and it has also been implicated in the pathogenesis of atherosclerosis, congestive heart failure, pulmonary hypertension, cardiac arrhythmias and stroke. Several studies showed that obstructive sleep apnea is associated with an increased risk of cardiovascular morbidity and mortality. However, a number of trials that assessed the effect of continuous positive airway pressure treatment have shown a reduction in blood pressure, decrease in cardiac arrhythmias, improvement in left ventricular function and reduction in incidence and mortality of cardiovascular diseases. Despite the available effective therapy the majority of individuals with obstructive sleep apnea and cardiovascular disease remains underdiagnosed and untreated.