It is generally considered that obstructive sleep apnea is a potential cause of heart failure (HF), and insomnia and central sleep apnea are results of HF. However, the number of reports describing the bidirectional relationship between sleep disorder and HF has increased. Sleep disorder may contribute to left ventricular diastolic dysfunction via left atrial overload, left ventricular remodeling, pulmonary hypertension, and atrial fibrillation, which lead to HF with preserved left ventricular ejection fraction. Overnight rostral fluid shift and lung congestion may lead to airflow obstruction in the upper pharynx and stimulate pulmonary irritant receptors, which induce hyperventilation and sleep disorder.