By improving body composition, such as fat, lean body mass and total body weight, an exercise program can be an effective treatment of obesity. The effects of exercise on obesity have been confirmed via various approaches such as type, intensity, duration, frequency, and combination with diet. Combined exercise and diet is the most efficient strategy for weight loss, and exercise alone could improve metabolism irrespective of weight loss. In addition, physical activity, including exercise, is emphasized to avoid a 'yo-yo' phenomenon. Exercise increases lipolysis stimulated by such factors as catecholamine, growth hormone (GH), and hormone sensitive lipase (HSL). Moreover, changes in insulin and cortisol through exercise affect adipose tissue, which is known as not only an energy storage locale, but also as an endocrine organ. Adipocytokines secreted by adipose tissue respond to signals that modulate metabolism and inflammation. Exercise has generally shown positive effects on adipocytokines, and these effects increase in conjunction with a hypocaloric diet. However, a long duration and a high intensity of exercise could induce an inflammatory response. This review summarizes the effects of exercise on obesity treatment, which contributes to the exercise and nutritional fields, particularly of community nutritionists. (J Community Nutrition 8(2): 76-89, 2006)