Obstructive sleep apnea (OSA) exerts several effects that may be particularly deleterious in patients with heart failure (HF). OSA should be considered especially in HF patients who are obese or have the metabolic syndrome, systemic hypertension, or pulmonary hypertension. HF patients in whom OSA is suspected should undergo a full evaluation by a sleep specialist, including a polysomnogram, to diagnose OSA and differentiate this disease from central sleep apnea. Those found to have OSA should then receive continuous positive airway pressure and/or other interventions, and standard disease management strategies should be used to maximize compliance. Those who cannot tolerate continuous positive airway pressure may be candidates for mandibular advancement devices or surgical therapies including tracheostomy. Standard HF medications should be used to treat HF, and optimization of fluid balance may help minimize OSA severity. However, it is still unknown whether treatment of OSA in HF patients will reduce hospitalizations or mortality.