This study was performed to investigate the growth rate, hematological and serological changes of the rats when they were fed with the high fat diets supplemented with or without the tannic acid for five weeks. Thirty-two Sprague-Dawley male rats(235.7pm10.7g;of;body;weight)$ were randomly divided into four groups, control group and three treatment groups(T1, T2 and T3). Rats in control group were fed with the high fat diet containing $15\%;lard,;1\%$ cholesterol and $0.5\%$ sodium cholate(wt/wt) which was modified from the formula of American Institute of Nutrition (AIN)-76 diet and rats in treatment groups were fed with above diet supplemented with $0.25\%(T1),;0.5\%(T2)$ or $0.75\%(T3)$ of tannic acid(wt/wt), respectively. The supplementation of tannic acid(TA) did not affect the final body weight, gain of body weight and feed intake of rats in both control and treatment groups. The numbers of red blood cells, hemoglobin concentrations and hematocrit values in blood of rats showed no significant differences between control group and treatment groups. The glucose concentration and albumin/globulin(A/G) ratio of rats in treatment groups were slightly lower than that of control group without significance. The values of total protein, albumin and globulin showed no significant differences between control group and treatment groups. The values of total cholesterol, low density lipoprotein­cholesterol and atherogenic index in sera of rats in treatment groups were much lower than that of control group without significance. The values of triglycerides in sera of rats in T3 group were significantly lower than that of control group (p<0.05). The values of AST and ALT in sera of rats in T3 group were significantly lower than that of control group (p<0.05). Thus supplementation of tannic acid to high fat diet could be effective to reduce the serum lipid levels such as total cholesterol, high density lipoprotein-cholesterol and triglycerides which were regarded as to cause the cardiovascular diseases.