In the present study, we investigated the effects of a lO-week strength training program on stress reactivity. Thirty five college women were assigned randomly to one of three groups : high intensity strength training (n=12), moderateintdnsity strength training (n=12),or control condition (n=11). All subjects underwent psychological, physical fitness and cardiovascular stress reactivity assessments before and after the 10-week training period. Tests of physical fitness included muscle strength and endurance (muscular fitness), body composition, and cardiovascular fitness, including maximal oxygen uptake (VO_2max) and minutes to reach 85% of age-predicted heart rate maximum. Measures of physical self-efficacy assessed perceived confidence for various muscular tasks. Heart rate (HR),systolic blood pressure (SBP), and diastolic blood pressure (DBP) responses were measured during psychosocial stress. The results demonstrated that training at both strength intensities significantly improved muscular fitness and body composition, whereas neither high nor moderate intensity training altered aerobic fitness. It was also found that strength training significantly reduced cardiovascular reactivity upon exposure to various psychosocial stressors in college women. There was a negative association between cardiovascular reactivity and physical self-efficacy. While it is clear that the reductions in physiological responses to stress were independent of the aerobic components, cognitive-behavioral factors may play some important roles in the modification of psychophysiological responses to stress.