The present study examined the relationship between aerobic exercise participation and physiological stress responsivity to psychosocial stressors. Male subjects (N = 107) who were either intense aerobic exercisers, moderate aerobic exercisers, or nonexereisers completed a telephone interview, a personality assessment battery, a life stress questionnaire, and a physical exercise and hobby questionnaire. Subjects then participated in a stressful laboratory procedure where they faced two stressors: an electric shock procedure, and a difficult “intelligence test.” Pulse rate, finger pulse volume, and skin resistance were assessed during the entire laboratory procedure. Although results demonstrated consistent significant cardiovascular (i.e., pulse rate and pulse volume) differences among the exercise groups during the entire laboratory procedure in that exercisers were less physiologically reactive to the stressors and the recovery periods, most of these results failed to reach significance when statistically controlling for the baseline/anticipation-of-stressors physiological measures. The implications of this study for further research are discussed.