In dogs prepared under thiopental anesthesia and then immobilized with decamethonium (C10), injn. of d-amphetamine causes a progressive increase in the frequency of the eeg. with a corresponding decrease in amplitude. These effects are max. within the 1st hr. When unanesthetized dogs are gently roused from sleep and then fully alerted, there is a rise in the frequency of the eeg.,accompanied by a decrease in amplitude. When d-amphetamine is injected into unanesthetized dogs, there is an increase in motor activity, the peak effect being reached within the 1st hr. There is some evidence for an increase in the frequency of the eeg. These findings suggest that the effects of d-amphetamine on the eeg of the dog are parallel to its effects on behavior.