Sleep EEG variables were compared in an adolescent population consisting of 11 anorectic girls, 11 young depressed patients and 11 healthy volunteers matched for age and sex. Anorectic patients differed from depressed patients in a greater number and a higher length of awakenings. In comparison with controls, anorectic patients showed less sleep efficiency, a higher length of awakenings and less REM sleep. When anorectic patients were divided in restricting and bulimic subtypes, the bulimic anorectics showed an increase in stage 3 of sleep. These results do not support a direct association between eating disorders and affective disorders. Sleep EEG variables were not significantly correlated to the Body Mass Index.