Fluoxetine is associated with substantial objective and subjective sleep disturbance in adults with major depressive disorders. In this preliminary report, the effects of fluoxetine on sleep electroencephologram (EEG) are described in 6 children and adolescents with nonpsychotic major depression. Fluoxetine increased light Stage 1 sleep, the number of arousals and rapid eye movement (REM) density. REM latency was largely unaffected. Oculomotor abnormalities were also evident on treatment, accompanied by an increase in myoclonic activity. Subjective sleep was also disturbed on treatment. These results are in keeping with those observed in depressed adults treated with fluoxetine.