Despite the high prevalence of obstructive sleep apnea (OSA) syndrome, no ideal therapy has emerged to date. Based on recent randomized trials, continuous positive airway pressure (CPAP) therapy is the treatment of choice. Although CPAP can prevent pharyngeal collapse in virtually all patients who choose to wear it, poor patient adherence with treatment limits its effectiveness. Although convincing data exist that treatment with CPAP can alleviate the neurocognitive sequelae of OSA, data on cardiovascular complications are more limited. Several recent reports support a lowering of nocturnal and daytime blood pressure with CPAP, but data on the prevention of myocardial infarction and cerebrovascular events are currently lacking. Patient adherence with CPAP can be improved with optimization of mask comfort, heated humidification, and intensive support and education. For those who remain poorly compliant, alternative therapies such as autotitrating devices and oral positive airway pressure can be considered. Further research into the basic mechanisms underlying OSA will be required for new therapeutic targets to develop.