PURPOSE: We wished to introduce the curative effect of biofeedback in children with urge syndrome and dysfunctional voiding, and examine the durability of effect and the difference in response to medication before and after biofeedback. MATERIALS AND METHODS: There were 15 patients with urge syndrome and 8 with dysfunctional voiding. Average age was 8.2 years old (range, 4-16 years). Pelvic floor relaxation biofeedback, voiding biofeedback, and intravesical biofeedback were enforced with 4-18 sessions (average, 7.4). We defined the patient with disappearance of more than 90% of symptoms as 'improved', disappearance of 50 to 90% as 'partially improved', and the rest as 'not improved'. We assessed the degree of improvement between groups, and changes in uroflowmetry, functional bladder capacity and response to medication after biofeedback. RESULTS: Nine (60%) of the 15 patients with urge syndrome and 4 (50%) of the 8 patients with dysfunctional voiding showed improvement, and the overall response rate was 56% (13 of 23 patients). The mean follow-up period was 7.6 months, and the therapeutic effect lasted for 5.1 months. Among the 13 patients who were refractory to medical treatment, 8 (61%) improved and 3 with partial improvement responded well to medication after biofeedback. There were significant improvements in uroflowmetry findings; the numbers of bell shape and discordant shape (fractionated, staccato) before and after biofeedback were 7, 14 and 19, 4, respectively. Functional bladder capacity was also improved significantly from 177ml to 236ml (p=0.014). CONCLUSIONS: Biofeedback is an effective and safe treatment modality in most patients with urge syndrome and dysfunctional voiding.ope