Male rat pups were deprived of active (REM) sleep by giving daily injections of clomipramine between 8 and 21 days after birth. At the age of 55 days their ambulation and defecation in the open-field were tested. Thereafter, beginning at the age of 66 days, the voluntary ethanol consumption of the rats was tested for 4 weeks. Compared to saline-treated rats, the CLM rats consumed more ethanol, tended to be more active in the open-field, and responded with a decrase in ambulation to an ethanol dose which stimulated locomotion in controls rats. These results indicate that neonatal treatment with clomipramine has an influence on later ethanol-related behavior in rats.