The effect of vasopressin and oxytocin on cerebral electrical activity, somatic behavior, heart rate and rectal temperature of non-anesthetized rabbits was studied. Both peptides induced EEG and behavioral activation and proved to be active in modifying heart rate and rectal temperature. EEG and behavioral changes, as well as autonomic effects seemed to be independent of one another, thus suggesting different points of attack of the peptides at CNS level.