The aim of this study was to establish the prevalence and associated factors of enuresis nocturna and to better understand nocturnal bladder control in Turkish children. A randomized epidemiological study was performed among primary school children, aged four to 12 years, living in Aydin, Turkey. After data collection via a self-administered questionnaire completed by the parents, data of 2,300 children were accepted for the analysis. The overall prevalence of reported marked nocturnal enuresis (at least weekly) was 11.6 percent and of day wetting 0.8 percent. Enuresis was more frequent in boys than in girls. Age, family history of enuresis, large family size, urinary tract infections and low parental socioeconomic class were all statistically associated with reported enuresis nocturna. Familial history among the enuretics and non-enuretics was 40.7 percent and 9.5 percent, respectively. Of the enuretics, 11 percent were treated professionally, 65 percent were treated traditionally by the family and 25 percent sought no help to manage the enuresis. A reference age of 2.9 +/- 1.6 years was calculated for nocturnal bladder control of the children studied. These results suggest that prevalence of enuresis nocturna and development of bladder control in Turkish children are not so different from that seen in other European and Middle East countries, and that the most significant factors associated with enuresis are socioeconomic and familial ones. Turkish families do not have a high level of concern about enuresis, even in the older children. This study demonstrated that enuresis is a sizable problem in Turkey and that a great ignorance about enuresis by both parents and physicians exits.