To study the effect of dietary $omega 6/omega 3$ fatty acid ratios on the preneoplastic lesions and lipid peroxidation in rat hepatocellular chemical carcinogenesis, placental glutathione S-transferase(GST-P) positive foci area and numbers, glucose 6-phosphatase(G6Pase) activity, thiobarbituric acid reactive substances (TBARS) were measured. Male Sprague-Dawley rats were fed 5 different diets-low $omega 6/omega 3$ ratio with fish oil (Low-F), low $omega 6/omega 3$ ratio with perilia oil(Low-P), moderate ratio with perilia oil(Moderate), blend of 10 different commercial fats and oils(High-BL) and high $omega 6/omega 3$ ratio(High)-for 8 weeks. Hepatocarcinogenesis was induced by modified Ito model. The area of GST-P positive loci was the lowest in Moderate group and in ascending order of Low-F < Low-P < High-BL < High. But statistically, only Moderate and High groups were significantly different. The number of GST-P positive foci showed the same trend as foci area. The activities of G6Pase, membrane stability marker, were increased as $omega 6/omega 3$ ratio decreased. Lipid peroxidation values (TBARS) were the lowest in Low-F group and it is significantly different from Moderate, High-BL and High groups. When dietary $omega 6/omega 3$ ratio was moderate(4.06), hepatocarcinogenesis was suppressed compared with high or low $omega 6/omega 3$ ratios. Blend fat, commonly consumed among Koreans, did not show any suppressive effect on carcinogenesis because of high ratio(6.7). These results suggest that dietary $omega 6/omega 3$ ratio influences hepatocellular chemical carcinogenesis. It is recommended that appropriate $omega 6/omega 3$ ratio should be around 4.0. and we recommend to use more $omega 3$ fatty acid in food preparation to reduce the risk of hepatocarcinogenesis.