This paper reviews literature and clinical experiences on the neurobiological and psychological aspects of sleep in children with mental retardation. The lack of a universal, operational definition of sleep disorders is noted, and a study is cited in which 61% of a group of 20 children (ages 2-13) with developmental disabilities were found to have sleep problems. DIMS (disorders initiating and/or maintaining sleep) is discussed as a frequent type of sleep problem, with emphasis on the need to establish a consistent behavioral routine prior to sleep onset and the need to gradually and systematically "shape" the child to remain in bed and return to sleep. Other sleep disorders discussed include nightmares, night terrors, and excessive sleepiness/sleep stage abnormalities. (12 references) (JDD)