Background: Enuresis is widely regarded as parasomnia because it occurs only during the NREM sleep. Polysomnography can be used to monitor appropriate physiologic variables associated with the child's sleep related problems. Aim: is to study the sleep pattern in Egyptian children who are suffering from primary nocturnal enuresis. Methodology: Twenty children with primary nocturnal enuresis and ten healthy children as control group were included in our study. Patients collected from outpatient clinics, Pediatric Department, Benha University Hospital. During the period from March (2015-2016). The following investigations were done for all Patients: urine analysis and culture, RBS, Ca, Na±,creatinine, pelvi-abdominal US, lumbosacral X-ray, uroflometry, voiding cystometry and Polysomnogram. Results: Uroflometric tests were normal in all cases excluding local urological causes of enuresis. Cystometric measurement of the bladder capacity revealed that three out of twenty patients (15%) had reduced bladder capacity and seventeen patients (85%) had a normal bladder capacity. A statistically significant difference (p=0.001) was observed in the number of awakenings, where the patients showed a significantly higher number of awakenings. A statistically significant difference (p=0.002) was observed in delta wave sleep where the patients showed a significantly less delta sleep activity and lower sleep efficiency than the control groups. REM sleep percentage was low in enuretic children though the difference was not statistically significant (p=0.142). Conclusion: Monosymptomatic nocturnal enuresis could be explained by a multifactorial etiology. Hence the sleep disturbances with the consequent urodynamic findings seem to be the cornerstone such a problem.