This study determined the effect of a 10‐week step aerobics training program on aerobic power and body composition of college‐age women (mean age, 19.4 years). Subjects in the experimental group (n = 21) exercised three times per week for 10 weeks, at an intensity that represented 76% of maximal heart rate. A control group (n = 28) did not exercise. All subjects performed a maximal treadmill test, were hydrostatically weighed, and were measured for maximal buttocks, thigh, and calf girth prior to and on completion of the study. Compared with the control group, the experimental group showed significant (p≤0.05) improvement in peak oxygen consumption (11.7%), maximal minute ventilation (6.7%), and time to exhaustion on the treadmill (33.1%). There was no significant (p>0.05) change in percent body fat in either group. Thus, it appears that step aerobic training can be an effective method of improving aerobic power in college‐age women. However, while the acute caloric requirement of step aerobics compares favorably with other modes of exercise, the duration and frequency of training used in the current study was not adequate to affect body composition positively in this group of women.