We assessed the prevalence of sleep disordered breathing (SDB) and investigated its effects on the muscle functional capacity and quality of life (QoL) among chronic kidney disease (CKD) Egyptian patients, either maintained or not maintained on hemodialysis (HD).The study population comprised 100 CKD patients who were divided into patients maintained on HD (n = 60; M/F = 28:32) and patients not maintained on HD (n = 40; M/F = 24:16). Patients were observed overnight using the pulse-oximetry technique and further subdivided into patients with SDB and patients without SDB, according to their calculated oxygen desaturation index (cutoff 5). All patients were subjected also to estimation of Kt/V ratio (which is a measure for the efficiency of HD), body-composition analysis, biochemical analysis, muscle functional capacity, and QoL measurements using standard methods and questionnaires, respectively.Primary outcomes were intergroup differences regarding physical capacity and muscle performance, QoL, and body-composition measurements. CKD patients in general, either maintained on HD or not, suffer from SDB, and the levels of urea and creatinine may increase the incidence of SDB in CKD patients not maintained on HD. CKD patients maintained on HD with SDB had poorer functional capacity, physical performance, and muscle composition, in comparison with those without SDB.Overall, SDB appears to partly contribute to the total diminished functional capacity of HD patients. Thus, CKD patients maintained on HD with SDB had significantly lower sleep quality and QoL as compared to those not maintained on HD with or without SDB.