Background: nocturnal enuresis (NE) has a negative impact on children's health and imposes a long-term burden on families. With increasing the awareness and improving the cultural conditions more attention was given to NE. Objective: To assess the frequency and associated risk factors of NE in a sample of primary school children in the Sharkia Governorate. Patients and methods:The study was carried out in two randomly selected schools (Al Salam primary school and Tal Moftah primary school) in Abo Hammad district, Sharkia Governorate. The sample included children who had monosymptomatic, primary, or secondary nocturnal enuresis including 454 children ages 6-12 years. Results: The frequency of NE was (8.8%). Children experienced more NE if they drank beverages containing caffeine during the day (12.2%). About 42.9% and 43.3% of children had constipation and urinary tract infection respectively suffering from NE. All children with social problems were belonging to the nocturnal enuresis group. Conclusion: Nocturnal enuresis was a common problem in children. Most of its risk factors were preventable and treatable.