Behavioral and adrenocortical responses of rhesus (Macaca mulatta), bonnet (M. radiata), and crabeating (M. fascicularis) macaques were compared in their home cages, during exposure to novelty and during physical restraint. Both behavioral and adrenocortical responses differentiated species in each condition. In all conditions, post-test corticosteroid levels were highest for crabeaters and lowest for rhesus. Rhesus were the most active behaviorally, and bonnets were the most passive, while crabeaters exhibited the greatest signs of behavioral disturbance. Relationships between adrenocortical and behavioral responses varied between groups. Both adrenocortical and behavioral profiles were in accord with the behavior of these three species under more natural conditions. The role of psychophysiological responses in general behavioral dispositions toward the environment is discussed. It is concluded that behavioral dispositions, inclusive of psychophysiological responses, may vary qualitatively even among closely related primate species.