The efficacy and safety of desmopressin (Minirin/DDAVP) treatment compared with imipramine were investigated in a multicentre, open, cross-over design in 57 patients, aged 6-15 years, affected by nocturnal enuresis to establish the best therapeutic approach to this condition. After a two-weeks observation and control period, patients were randomised to one of two groups: intranasal administration of desmopressin, 30 micrograms/day for three weeks, followed by imipramine, 0.9 mg/kg for a further three weeks, or imipramine 0.9 mg/kg for three weeks, followed by desmopressin, 30 micrograms/day for a further three weeks. Following treatment, all patients were observed for a further two weeks. Administration of either treatment protocol resulted in a statistically significant decline in the number of enuretic episodes per week compared to the control. The greater antidiuretic effect observed in the group receiving imipramine followed by desmopressin suggests the two compounds have different profiles. Also, when the treatment period was compared with the follow-up, the antidiuretic effect had a longer duration in the group initially given imipramine. No further improvement was seen when desmopressin was administered first, with a mild worsening of the effect sometimes occurring, suggesting a different carry-over effect between the two treatments. This suggests that desmopressin offers a better approach to the management of nocturnal enuresis.