OBJECTIVE Two hundred and thirty-eight children (170 males, and 68 females) with nocturnal enuresis were retrospectively studied for lower urinary tract problems. Surgical correction of subclinical organic obstruction in the lower urinary tract was evaluated for the improvement of bed-wetting. METHODS One hundred and fifty-five micturating cystourethrography (MCU), and 89 urodynamic studies were performed. Optic internal urethrotomy was done in a boy, and meatoplasty in a girl for urethral 'ring' stenosis (URS). RESULTS Nocturnal enuresis was found in 153 cases and nocturnal enuresis associated with daytime enuresis in 67 cases. Vesicoureteral reflux was found in 30, URS in 42, and posterior urethral valve in 3 cases on MCU. Detrusor instability was recognized in 39.4% of 38 cases of nocturnal enuresis associated with daytime enuresis and in 25.0% of 51 cases of nocturnal enuresis. Surgery brought 73.8% improvement of bed-wetting in 42 cases. CONCLUSIONS Surgical correction of subclinical obstruction in the lower urinary tract might contribute to the earlier resolution of bed-wetting in children with nocturnal and/or diurnal enuresis.