Since it has generally been considered that high-hat diets promote carcinogenesis, fat intake of less than 30% of total calories has been recommended to reduce the risk of cancer. Specific dietary guidelines for fat intake to reduce the risk of colon cancer have not yet been established. In order to determine the level of dietary fat needed the risk of colon cancer, rats were fed one of four experimental fat diets, very low(7% of total calories from corn oil, VLC), low(15% LC), medium (30%, MC), and high fat(45%, HC). Cell proliferation as an intermediate biomarker of color carcinogenesis was measured by the in vivo incorporation of bromodeoxyuridine into DNA. Fecal lipid excretion was measured by gravimetric method. As fat levels in the diet increased, fecal lipid concentrations also increased (VLC<LC<MC<HC, r=0.78, p<0.001). In the proximal colon, cell proliferation was significantly lower in groups fed VLC, LC and MC diets compared to that of the HC-fed diet(p<0.05). In the distal colon, however, cellular proliferation was significantly lower only in the VLC group. These results suggest that effective dietary fat levels for reducing the risk of colon cancer may vary with the sites of colon cancer. In addition, fecal lipid levels were more strongly correlated with cellular proliferation of the distal colon than that of the proximal colon.