Obstructive sleep apnea-hypopnea syndrome (OSAHS) is a prevalent condition in the general population. It is associated with increased cardiovascular risk and often goes unrecognized. Its diagnose requires a high degree of clinical suspicion, particularly on the part of cardiologists, and it may be confirmed by polysomnography. Continuous positive airway pressure (CPAP) therapy is highly effective, since it improves sleep breathing pattern, promotes restful sleep and thus enhances the quality of life of these patients, in addition to attenuating or reversing many cardiovascular complications related to OSAHS. This paper addresses the pathophysiology and clinical features of cardiovascular comorbidities associated with the syndrome.