Women, considering swimming as a form of exercise to lose weight, have been discouraged from doing so, since researchers suggest that swimming does not burn fat as efficiently as land exercise. The purpose of this study was to compare carbohydrate and fat utilization by women engaging in two different forms of exercise, walking and swimming, at the same intensity and duration. Subjects were 20 moderately trained female subjects, walkers (W) = 10 and swimmers (S) = 10; ages 18-40 years. Measurements of blood free fatty acids (FFA), glycerol, lactate, glucose, free fatty acid turnover (FFAT), respiratory quotient (RQ), and fat oxidation were made during 60 minutes of walking or swimming at the same exercise intensity. Multivariate analysis of variance determined no significant differences between groups in net energy expenditure (NEE), RQ, fat oxidation, blood FFA, glycerol, glucose, and FFAT(p > .05). There was a significant difference between groups in blood lactic acid levels (p < .01). Since it was found that swimming and walking at the same duration and intensity bum similar amounts of fat and carbohydrate as energy sources during exercise, women may find swimming to be a viable form of exercise for weight control.