Background: Primary Nocturnal Enuresis (PNE) is an important developmental problem for school age children and children with PNE seem to have psychological problems which may be the results or the etiology of enuresis. PNE is multifactorial and many risk factors have been described to explain this phenomenon. Objective: To determine the prevalence of PNE in Qena Governorate primary school children and to assess risk factors that can cause or affect the disease. Methods: a cross-sectional study of PNE was performed. We distributed 10580 questionnaires in 17 primary schools in Qena Governorate. After exclusion of secondary, diurnal or mixed enuresis, we detected the prevalence and risk factors of PNE. Results: Students with enuresis were 1065 (11.4%). The prevalence of PNE was 10.13%. PNE was higher in younger age, male gender and large families, while positive family history, deep sleep, low socioeconomic, threatening toilet training and the response of the parents and siblings with psychic abuse, are the main risk factors of PNE. We found that the psychological and stressor factors are associated with mild to moderate forms of enuresis. The child responded to enuresis by depression, isolation, nervousness and violence and this affects his school success. Conclusion: The prevalence of PNE in primary school children in Qena Governorate constitutes about 10.13%. We recommend that the parents should be well informed about these risk factors to avoid them and advice them to seek for medical and psychiatric help. [Egypt J Neurol Psychiat Neurosurg. 2013; 50(2): 163-169]