Sleep-disordered breathing (SDB), including obstructive sleep apnea (OSA) and central sleep apnea (CSA), is highly prevalent and frequently unrecognized in patients with chronic heart failure (HF). Untreated SDB may worsen acute decompensation of HF and delay recovery by increasing vascular inflammation and oxidative stress, impeding control of the blood pressure, and promoting arrhythmias. Untreated OSA doubles the risk for developing HF, and patients with HF who develop OSA are thought to have a worse prognosis than patients with HF alone. Similar to the findings in the general population, treatment of OSA appears to reduce cardiovascular morbidity and mortality in HF. The presence of CSA is associated with increased mortality in HF patients. Efficacious suppression of central sleep apnea with continuous positive airway pressure therapy may reduce mortality in HF.