Hypertension is a well established cardiovascular risk factor and its deleterious effects had already been largely studied. Although the benefits of adequate blood pressure (BP) control have already been demonstrated, the prevalence of persons who fail to achieve such control is alarming. A number of causes for uncontrolled hypertension can be listed. According to recent guidelines, obstructive sleep apnea (OSA) is an important, although neglected cause of hypertension that is resistant to optimal medical therapy. Specific treatment for OSA with continuous positive airway pressure (CPAP) can be a helpful adjunct to conventional pharmacological therapy to attain controlled BP levels.