This study was undertaken to investigate the effect of caffeine level on food intake and weight gain in 120 Sprague-Dawley rats of different ages and sexes for 3 weeks. The results were as following : the food intake of caffeine group was significantly lower than that of caffeine free group in young and adult rata(p<0.05). The bo여 weight gain, body weight gain efficiency ratio and food efficiency ration of rats were not significantly different between two groups. The results showed that body weight gain was not affected by increased caffeine level in young and adult rats.