Many recent prospective, long-term, controlled studies suggest that in untreated patients with sleep apnea, the risk of death from all-causes and particularly cardiovascular causes is increased. There is a relation between the severity of this disease and cardiovascular risk, but the effective treatment with nasal continuous positive airway pressure significantly reduces the mortality associated with this medical condition. This article examines the growing evidence that links obstructive sleep apnea with cardiovascular outcomes and specifically with an excess of mortality.