Amphetamine was administered to a group of rats trained on a nondiscriminated avoidance procedure. An intraperitoneal dose of 2.0 mg/kg caused about a 75% increase in response rate for the three-hour session. Doses of atropine, Tremorine, eserine, and 4-(1-naphthylvinyl)-pyridine (NVP), an inhibitor of the enzyme choline acetylase, which were ineffective in themselves, markedly affected the increase in rate observed after amphetamine. The quarternary amine of NVP was without effect on the amphetamine response. Those agents that decreased cholinergic function, either by blocking the effect of acetylcholine or by preventing its synthesis, augmented the stimulating effect of amphetamine. Cholinergic stimulants, on the other hand, significantly antagonized the behavioral effects of amphetamine. © 1969 Springer-Verlag.