To study the self-image of children between 8 and 12 years with nocturnal enuresis, and to correlate the findings with age, sex, clinical symptoms, primary versus secondary enuresis and treatment failures. The study-group embraced 50 university hospital, and therefore selected therapy-resistant nocturnal enuresis-children, 27 boys and 23 girls. The mean age was 9.8, which means children aged between 8 and 12 years. Children were classified into two age groups: I=8-9 years and II=9-12 years. A total of 41 out of 50 had primary nocturnal enuresis. The mean number of treatments before intake was 5.6, A=1-4, B=5-8, C=9-12. Seventy-seven children without nocturnal enuresis were included in the control group, 31 boys and 46 girls. The method we used to measure the perceived competence of the children on specific domains of their life was the Dutch translation and also validation of the "Self-Perception Profile for Children" by Harter. The testing was performed before and after therapy. Children with nocturnal enuresis have a significantly lower perceived competence than children without nocturnal enuresis, concerning physical appearance (p<0.05) and global self-esteem (p<0.01). There is a main effect of gender (p<0.01) and age (p<0.05) concerning scholastic skills. There is a correlation with the number of treatment failures. The more treatment failures, the lower the self-esteem. After successful treatment, there is an improvement of 'athletic competence' and 'global self-esteem', but it is not significant. Nocturnal enuresis has important negative effects on the self-image and performance of children. Perceived competence was lower in girls than in boys with enuresis, and it was significantly lower in the higher age than in the lower. Children with day-time and night-time incontinence have a significantly decreased perceived competence on scholastic skills compared to children with nocturnal problems only. Successful treatment tended to increase athletic competence and global self-esteem.