Supplementation of omega-3 fatty acids is very effective in reducing oxidative stress through the improvement of antioxidant enzymes activities . Fish and flaxseed oils are nutritional supplements have a high concentration of omega-3 fatty acids.Flax seed oil is rich in alpha linolenic acid (ALA) while fish oil is rich in eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). In this study we aimed to compare the effects of flaxseed and fish oils in reducing oxidative stress especially in attenuating DNA damage through the evaluation of urinary 8-hydroxyguanosine (8-OHdG) in experimental diabetes. The main finding in our study was the reduction of urinary isoprostanes and 8-OHdH , in addition to the reduction of insulin resistance during diabetes. In conclusion, flaxseed and fish oils administration has a potential effect on decreasing insulin resistance in diabetic rats through the scavenging of free radicals and increasing superoxide dismutase . This study also concluded that ,fish oil was more effective than flaxseed oil.