Background: Nocturnal enuresis is caused by a mismatch between nocturnal urine production and bladder capacity. Together with a presumed decreased arousability, this results in an inability to awaken in response to a full bladder. According to recent findings, a disrupted sleep might play a role in the pathophysiology of enuresis. Case: A 7-year-old boy was diagnosed with primary nocturnal enuresis caused by nocturnal polyuria and a concomitant parasomnia, somnambulism. A polysomnographic study was performed before treating the nocturnal enuresis with the oral lyophylisate formulation of desmopressin (melt). After 1 day of treatment, both nocturnal enuresis and somnambulism disappeared. Treatment was ceased after six months. One week later, the child started to produce more urine and redeveloped nocturnal polyuria. Somnambulism reappeared followed by nocturnal enuresis two weeks later. The same treatment protocol was started up, resulting in disappearance of both nocturnal enuresis and somnambulism. Conclusion: This case report documents the beneficial effect of desmopressin melt on both nocturnal enuresis, caused by nocturnal polyuria, and a concomitant parasomnia in particularly somnambulism.