The purpose of this study is to determine the effects of the aerobic exercise type on macronutrient self-selection. Male Sprague-Dawley rats were placed on a macronutrient self-selection diet for 4 weeks. For this purpose, mixed feeds were prescribed for the rats while they were forced to swim and run for 4 weeks. Animals were either swimming exercise or treadmill running exercised at 20m/min(60min/day). Cumulative daily energy and macronutrient intake were determined during this period. The running exercise group gained weight much more than the control group, while the swimming exercise group lost weight less than the control group. Such findings suggests that the former group took more feed. On the other hand, the dietary efficiency of the control group was higher, which implies that no physical exercise would result in a higher dietary efficiency. And there was significant difference of total dietary and calorie intakes among the three groups, Although insignificant in statistical means, it was found that the running group took feed most, which is attributable to the homeostasis requiring the supplementation of the calorie lost by exercise. Also, the running exercise group took the protein and carbohydrate most. while the control group took fat most. The decrease of fat intake by the running exercise group suggests the possibility that the in-body enzymes should adapt themselves to the changing in-body condition caused by the endurance exercise. In contrast, it is conceived that the more intake of the carbohydrate may be attributable to the need of supplementing the nutrient lost by the endurance exercise. As discussed above, the endurance exercise group took carbohydrate and protein and less fat than control group. In particular, it was found that the amount of feed intakes was affected much by types, intensity and duration of the exercises. All in all, such findings would apply to human beings. Now can increase the intakes of carbohydrate and decrease the intake of fat through an effective running exercise program and thereby, change our dietary patterns to the benefit of our body and simultaneously, prevent and adult\`s diseases by decreasing the in % body fat level.(Korean J Nutrition 33(8) : 794-801, 2000)