A number of novel and important observations have recently arisen that emphasize the interaction between sleep apnea and cardiovascular function. New evidence of a role for obstructive sleep apnea as an independent factor in the genesis of hypertension and nocturnal myocardial ischemia has been described. Advances have been made in the understanding of the acute impact of sleep-disordered breathing on hemodynamic function, and a better understanding of the interaction between sleep-disordered breathing and congestive heart failure is now emerging. There is now strong evidence that reversal of sleep-related breathing disorders by nasal continuous positive airway pressure leads to improvements in markers of cardiovascular outcome in selected patients with congestive heart failure. These findings augur well for the development of new diagnostic approaches and treatment strategies for patients with sleep apnea and coexisting cardiovascular disease.