Nineteen obese women were studied to determine the effects of two different exercise prescriptions which differed in the type of activity but were matched for total energy expenditure. All women met once per week for twelve weeks as a group to receive the same recommendations concerning dietary modification. A low fat, self selected diet of approximately 1200-1500 kcal was recommended. Ten women participated in a walking program four days/week (GP1) which progresses to 160 minutes per week at 70% HR max. The second group (GP2) of nine women did two days/week (up to 90 minutes/week) walking and two days/week resistance training (up to 90 minutes/week). The resistance training consisted of eight exercises, 8-15 repetitions, at 50-85% of 1 RM, and three sets. All exercises were supervised and attendance for all women was greater than 92% of all the sessions. Losses of body weight (BW) (-5.7 ± 1.1 kg and - 4.5 ± 1.0 kg for GP1 and GP2, respectively), body fat (-3.9 ± 1.1 kg and -4.9 ± 1.0 kg for GP1 and GP2 , respectively) and fat free mass (-2.1 ± .7 kg and -1.6 ± .9 kg for GP1 and GP2, respectively), and percent body fat (- 2.1 ± .7 and -1.5 ± .9 for GP1 and GP2, respectively) were significant over time for both groups with no significant differences between groups. However, GP1 tended to lose more percent body fat and FFM than GP2. Absolute RMR showed a nonsignificant decrease overtime for both groups (-139.7 ± 107.5 kcal/day and -48.1 ± 75.0 kcal/day for GP1 and GP2, respectively). RMR expressed per bodyweight (kg) or fat free mass was maintained for both groups over the experiment (+.4 RMR/kg and -1.1 RMR/FFM respectively for GP1 and +.6 RMR/kg and -.04 RMR/FFM respectively for GP2). In conclusion, the total energy cost of exercise rather than the type of activity seems most important in body composition and metabolic rate changes during weight loss.