The purpose of this study was to investigate the effect of dietary caffeine supplementation(0.033%/diet) on the plasma and liver lipid concentrations in rats. Twenty male Sprague-Dawley rats(body weight $200{pm}10;g$) were divided into two groups: the control group and the caffeine-supplemented group(0.033% caffeine-supplemented diet). All rats were fed an experimental diet, and deionized water was avaliable ad libitum for 6 weeks. Plasma lipid concentrations were measured with a commercial kit based on an enzymatic method, and liver lipid concentrations were measured using the Folch method. There were no significant differences in body weight gain, food intake or food efficiency ratio between the control and caffeine-supplemented group. The total cholesterol and LDL-cholesterol levels as well as the AI(athrogenic index) were significantly higher in rats fed the caffeine diet(0.033%) than in those fed the control diet. There were no significant differences in the liver total cholesterol and triglyceride levels between the control and caffeine-supplemented groups. Therefore, it seems possible that caffeine(0.033 g/100 g diet) may increase the plasma lipid concentration level in growing rats.