This review provides a historical background on sleep-related eating disorders, summarizes findings from a series of 38 adults, and presents a current classification. The “night—eating syndrome” was first reported in 1955; only nine reports on this syndrome appeared during the next 36 years, seven being single-case studies and two containing the objective monitoring of sleep, that is, polysomnography. In 1991 our sleep center reported on 19 cases, and in 1993 on 38 cases, diagnosed by polysomnography and clinical evaluations. Mean age was 39 years, mean duration of night—eating was 12 years, 66% were women, 68% had nightly binge eating, and 44% were overweight from night—eating. Sleepwalking was the predominant disorder responsible for night—eating; restless legs syndrome, obstructive sleep apnea, and various other conditions (including two cases of anorexia nervosa) were also identified. Cognitive-behavioral therapies were ineffective, but pharmacotherapy was very effective in controlling night—eating and inducing loss of excess weight, and often consisted of a dopaminergic agent taken with codeine at bedtime. Thus, sleep-related eating can be an occult but often treatable cause of obesity. Further research, utilizing polysomnography, is encouraged.