This research was done with the aim of studying prevalence of enuresis and associated factors to nocturnal enuresis amongst pre-primary school students in the city of Ahwaz. This research was of
cross sectional descriptive kind, whose statistics society was all the pre-primary school students in the city of Ahwaz in the educational year of 89-90 (20 I 0-20 11). In order to survey the prevalence of this disorder 920 pre-primary school students, using an clustered multistage sampling, were chosen, 807 parents out of this group filled in their children checklists' and were taken into account as the final samples in final analysis. To analyze the data, in addition to descriptive methods like abundance and percentage, Chi square deductive statistics method was used. Based on the results of this research, prevalence of enuresis in the studied subjects was 14.4%. 10.8%, 2.1 % and 1.5% of all subjects are by far affected by nocturnal enuresis, diurnal enuresis and compound enuresis. The research results showed that enuresis is meaningfully related to male gender (P=0.026), antecedent of enuresis in child's sisters and brothers (P=O.OOO 1), positive history of enuresis among child's parents (P=O.OOO I), excessive intake ofliquids (P=O.OOO 1) and excessive urination during the day (P=0.013).