Sleep disturbances are found in most depressive patients. Serotonin reuptake inhibitors, such as fluoxetine hydrochloride, seem to improve sleep by changing the depressive affect and the underlying biological mechanisms. Insomnia is an occasional adverse effect of the medication, but it was shown that only 2-3% of the patients with fluoxetine-induced insomnia discontinued the drug for this reason. We could not find any report of nightmares or night terrors under fluoxetine treatment. We report on four patients who experienced nightmares on fluoxetine monotherapy.