This study was observed the effect of n6 and n3 polyunsaturated fatty acids of dietary corn oil and fish oil which was supplemented with similar levels of tocopherol in high fat diet on the levels of tocopherol, malondialdehyde ( MDA) productions of plasma and tissues of rats. Also RBC hemolysis, superoxide dismutase (SOD) and glutathione peroxidase (GSH Px) activities In liver were determined. Male Sprague Dawley rats were fed high fat (40%Cal) diet which was different only In fatty acid composition for 6 weeks. Dietary (arts were beef tallow(BT) as a source of saturated fatty acid, corn oil(CO) for n6 linoleic acid (LA) and fish oil(FO) for n3 eicosapentaenoic acid(EPA) + docosahexaenoic acid (DHA). Plasma and liver tocopherol levels were lowered by n3 PUy4 but there was no difference in malondialdehyde(MDA) level by different dietary PUFA. However, MDA content of RBC and hemolysis were increased by n3 PUFA. MDA content, superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) activities in liver were increased in more unsaturated dietary fat groups. Especially, SOD activity was increased in proportion to the degree of fat unsaturation.