A group of Vancouver health professionals, including the authors, have studied the use of oral melatonin in the treatment of chronic sleep disorders in children with disabilities since the Fall of 1991. This review article is based on the first 100 patients, half of whom were visually impaired or blind. Children with neurological, neuropsychiatric, and developmental disabilities are predisposed to chronic sleep-wake cycle disturbances. Disorders such as blindness, deaf-blindness, mental retardation, autism, and central nervous system diseases, among others, diminish the ability of these individuals to perceive and interpret the multitude of cues for synchronizing their sleep with the environment. Melatonin, which benefitted slightly over 80% of our patients, appears to be a safe, inexpensive, and a very effective treatment of sleep-wake cycle disorders. The oral dose of fast release melatonin taken at bed-time ranged from 2.5 mg to 10 mg. Side effects or the development of tolerance have not been observed. Since the causes of sleep difficulties are extremely variable, not all children are candidates for treatment. For successful melatonin treatment, clinical experience is required, and the influences of other health problems and medications need to be considered. Further clinical and laboratory research in this field is imperative because melatonin treatment offers enormous health, emotional, social, and economic benefits to society, especially since multidisabled children with chronic sleep difficulties do not respond well to current therapeutic regimes.