• The primary endpoint will be the difference in the proportion of subjects who preferred each formulation at the end of the 6-week treatment period.
• The subjects will be asked a question regarding which treatment (Minirin® oral lyophilisate or Minirin® tablet) they preferred at the end of 6 weeks treatment.

• Efficacy will be measured as the difference in the incidence of bedwetting episodes during each 3-week treatment period, compared between formulations. [ Time Frame: 3 weeks ] [ Designated as safety issue: No ]
• The subjects will be asked to rate the ease of use of each formulation using a 100 mm Visual Analogue Scale (VAS), with 0 = I find it very easy to use this medicine and 100 = I find it very difficult to use this medicine. [ Time Frame: 3 weeks ] [ Designated as safety issue: No ]
• Subjects will be asked to complete a QoL questionnaire at visit 2 and visit 3. [ Time Frame: 3 weeks ] [ Designated as safety issue: No ]
• Safety comparison between the 2 formulations. [ Time Frame: 6 weeks ] [ Designated as safety issue: Yes ]
• Comparison of compliance between the 2 formulations. [ Time Frame: 6 weeks ] [ Designated as safety issue: Yes ]
• The subjects will be asked a question regarding which treatment (Minirin® oral lyophilisate or Minirin® tablet) they preferred at the end of 6 weeks treatment. [ Time Frame: 6 weeks (melt) and 6 weeks (tablet). Total 12 weeks. ] [ Designated as safety issue: No ]

• Efficacy will be measured as the difference in the incidence of bedwetting episodes during each 3-week treatment period, compared between formulations.
• The subjects will be asked to rate the ease of use of each formulation using a 100 mm Visual Analogue Scale (VAS), with 0 = I find it very easy to use this medicine and 100 = I find it very difficult to use this medicine.
• Subjects will be asked to complete a QoL questionnaire at visit 2 and visit 3.
• Safety comparison between the 2 formulations.
• Comparison of compliance between the 2 formulations.

To evaluate the preference of subjects for Minirin® oral lyophilisate treatment compared with Minirin® tablet treatment after 6 weeks.

To compare efficacy of the 2 formulations at the end of the 6-week treatment period using diary card data.

To compare ease of use of both formulations at 3 and 6 weeks using a VAS-scale. To validate a PNE Quality of Life (QoL) questionnaire. To evaluate safety. To compare compliance with the 2 formulations

To evaluate the preference of subjects for Minirin® oral lyophilisate treatment compared with Minirin® tablet treatment after 6 weeks.

To compare efficacy of the 2 formulations at the end of the 6-week treatment period using diary card data.

To compare ease of use of both formulations at 3 and 6 weeks using a VAS-scale. To validate a PNE Quality of Life (QoL) questionnaire. To evaluate safety. To compare compliance with the 2 formulations

• Drug: MINIRIN Oral Lyophilisate
• Drug: Minirin tablet

Inclusion Criteria:

• Children suffering from primary nocturnal enuresis with no organic pathology.
• Children of either sex, not below 5 and not above 15 years of age (not below 6 years in The Netherlands and France).
• Children with a minimum of 6 wet nights in 2 weeks.

Exclusion Criteria:

• Children who have previously been treated with desmopressin or other medications for nocturnal enuresis or enuresis alarms.
• Children receiving substances that are known or suspected to potentiate antidiuretic hormone, e.g. SSRI, tricyclic antidepressant drugs, chlorpromazine and carbamazepine.
• Diagnosed renal diabetes insipidus or central diabetes insipidus with an AVP (arginine vasopressin) deficiency.
• Proven urinary tract infection within the past month or a documented positive urine culture at the start of the study