This study was conducted to examine the effects of dietary xylooligosaccharides on lipoprotein lipase (LPL) activitiy in epididymal adipose tissue and lipid composition in serum of rats fed normal or high fat diet. Male Sprague-Dawley male rats weighing 100 $pm$ 10 g were randomly divided into four groups, two normal diets and two high fat diets containing 1% cholesterol and 10% lard. Two normal diets were classified into a basal diet (normal group) and that with 10% xylooligosaccharide diet (NX group). The high fat diet groups were classified into a HF group without xylooligosaccharides diet and HFX group supplemented with 10% xylooligosacchride diet. Experimental diets were fed ad libitum to the rats for 4 weeks and then they were sacrificed. Body weight, epididymal weight and abdominal weight in HF group were hevier than the those of normal group, but HFX group was significantly reduced compared to HF group. Relative body weight to epididymal weight and relative body weight to abdominal weight in HF group were increased to 50%, 51%, respectively, compared to normal group, but HFX group was reduced 22%, 16%, respectively, compared to HF group. The levels of serum triglyceride, total cholesterol, LDL-cholesterol and atherogenic index in HFX groups were significantly lower than those of HF group, whereas HDL-cholesterol levels were significant increased. Triglyceride contents of epididymal adipose tissue in HF group was increased to 39%, compared to normal group, but HFX group was reduced to 15.8%, compared to HF group. Cholesterol contents of epididymal adipose tissue in HF group was increased 121%, compared to normal group, but HFX group was reduced to 26%, compared to HF group. The activity of LPL in epididymal adipose tissue was increased to 259% in HF group, compared to normal group and HFX group was reduced to 66%, compared to HF group. These result of this study suggested that improved lipid metabolism observed in rats fed xylooligosaccharides may be caused by an alteration of LPL activity in epididymal adipose tissue and lipid composition in serum.