The intake of caffeine (CF) at 0.025, 0.05 or 0.1% for 21 days progressively reduced the body fat mass and body fat percentage in Sprague-Dawley (SD) rats fed on a high-fat diet with increasing administration level. Moreover, CF increased the serum concentrations of catecholamines and free fatty acids in SD rats orally administered with CF (5 mg/kg). These results suggest that the intake of CF reduced body fat by lipolysis via catecholamines. CF has potential as a functional food ingredient with an anti-obesity action.