Adult sleepwalking affects 2.5% of the general population and may lead to serious injuries. Fifty young adults with chronic sleepwalking were studied prospectively. Clinical evaluation, questionnaires from patients and bed partners, and polysomnography were obtained on all subjects in comparison with 50 age-matched controls. Subjects were examined for the presence of psychiatric anxiety, depression and any other associated sleep disorder. Isolated sleepwalking or sleepwalking with psychiatric disorders was treated with medication. All other patients with other sleep disorders were treated only for their associated problem. Prospective follow-up lasted 12 months after establishment of the most appropriate treatment. Patients with only sleepwalking, treated with benzodiazepines, dropped out of follow-up testing and reported persistence of sleepwalking, as did patients with psychiatric-related treatment. Chronic sleepwalkers frequently presented with sleep-disordered breathing (SDB). All these patients were treated only for their SDB, using nasal continuous positive airway pressure (CPAP). All nasal CPAP-compliant patients had control of sleepwalking at all stages of follow-up. Non-compliant nasal CPAP patients had persistence of sleepwalking. They were offered surgical treatment for SDB. Those successfully treated with surgery also had complete resolution of sleepwalking. Successful treatment of SDB, which is frequently associated with chronic sleepwalking, controlled the syndrome in young adults.