Background Heart failure (HF) is characterized by its high mortality, frequent hospitalizations, and reduced quality of life. Sleep-disordered breathing (SDB), one of the common comorbidities, accelerates the progression of HF. Objectives The objectives of the study were (a) to investigate the prevalence and type of SDB in HF patients and (b) to determine the predictors of SDB. Materials and methods In a cross-sectional analytic study, all eligible patients of Assiut Chest and Cardiology Department admitted (100 patients) during the period from August 2015 to March 2016 were included in this study. Clinical assessment, full-night attended polysomnography, and echocardiography were recorded and compared between patients with (SDB) (85 patients) and those without SDB (15 patients). Results SDB was found in 85% of patients [53% had obstructive sleep apnea (OSA) and 32% had central sleep apnea (CSA)]. OSA patients are characterized by higher BMI and neck and waist circumference. There was a higher prevalence of hypertension, as well as mean blood pressure, systolic blood pressure, diastolic blood pressure, in OSA patients. Loud snoring was the only clinical symptom associated with OSA as compared with CSA. CSA patients had a significant reduction in PaCO2. OSA patients showed a significant increase in desaturation index and time spent with oxygen saturation less than 90%. Maximum heart rate and brady/tachy index were significantly increased in OSA. Cycle length was significantly increased in CSA. Conclusion The prevalence of sleep apnea was high in patients with stable HF (85%). OSA was the predominant type (53%). The predictors of SDB were BMI (≥30), systemic hypertension, neck circumference more than 40 cm, waist circumference more than 110 cm, and e