Ashraf El-Mitwalli,1 Adel Salah Bediwy,2 Ashraf Ahmed Zaher,1 Tamer Belal,1 Abdel Baset M Saleh3 1Neurology Department, Faculty of Medicine, Mansoura University, Mansoura, 2Chest Department, Faculty of Medicine, Tanta University, Tanta, 3Chest Department, Faculty of Medicine, Mansoura University, Mansoura, Egypt Background: Children with nocturnal enuresis (NE) are believed to have deep sleep with high arousal threshold. Studies suggest that obstructive sleep apnea–hypopnea syndrome (OSAHS) and NE are common problems during childhood. We sought to assess the prevalence of OSAHS in children with refractory NE and whether its severity is associated with the frequency of bedwetting. Methods: The study group comprised 43 children with refractory monosymptomatic NE and a control group of 30 children, both aged 6–12 years. All subjects underwent thorough neurological examination, one night of polysomnography only for the patient group, and a lumbosacral plain X-ray to exclude spina bifida. Results: The groups were well matched. Two subjects of the control group had mild OSAHS. The mean age of the patients was (9.19±2.4 years), 26 were boys, and 67% showed frequent NE (>3 days bedwetting/week). Patients with NE had significantly higher rates of OSAHS (P<0.0001); three patients had mild, 12 had moderate, and eleven showed severe OSAHS. There was no significant statistical difference among patients having OSAHS in relation to age, sex, or family history of NE. The frequency of bedwetting was statistically significantly higher in patients with severe OSAHS (P=0.003). Conclusion: Patients with refractory NE had a significantly higher prevalence of OSAHS with no sex difference. The frequency of bedwetting was higher in patients with severe OSAHS. Keywords: nocturnal enuresis, refractory, OSA