Background: Sleep-disordered breathing (SDB) is highly prevalent in patients with advanced chronic kidney diseases (CKDs).Objective: To describe and compare the prevalence, severity, and patterns of SDB and associated nocturnal hypoxia among patients with advanced CKD, hemodialysis (HD) patients, and control group.Methods: Forty patients were recruited from outpatient nephrology clinics and hemodialysis units. Patients were stratified into two groups: conservative (n = 25), and HD (n = 15). 30 healthy individual enrolled as the control group. All participants completed polysomnography (PSG).Results: Case control study of forty CKD patients (15 HD and 25 conservative) [13(86.7%) and 20 (80%) men, mean age 62.73 ± 5.43 and 55.76 ± 9.03 year, BMI 40.83 ± 8.75 and 36.12 ± 16.53 kg/m, mean ESS 18.46 ± 3.20 and 17.84 ± 2.79), respectively, and 30 healthy participants served as the control. The prevalence of SDB in CKD was 33/40(82.5%). In the conservative group, AHI was 148.84 ± 147/h, [80% obstructive, 13% central, and 5% mixed apnea]. Among these conservative groups with OSA patients, 56% had severe, 31% moderate, and 12.5% mild OSA. While in the HD group, AHI 133.26 ± 111/h, [84.6% obstructive, 7.7% central, and 7.7% mixed apnea]. Among these HD groups with OSA, 63% had severe, 27% moderate, and 9% mild OSA. GFR was significantly correlated with AHI and ODI (r = À0.315, P < 0.05, r = À0.506, P < 0.001) respectively. AHI correlated with urea concentration (r = À0.094, P < 0.05). Increased creatinine, and decreased eGFR were significant risk factors of severe OSA. Predictors that reduced renal function were, decreased TST, delayed latency to REM sleep, and increased AHI.Conclusions: Severe OSA was highly prevalent among CKD. Urea was the stronger predictor of increased AHI.