This investigation was carried out on some sesame seed varieties, namely: Toshka 1, Shandaweel 3 and Giza 32 in order to study the utilization of sesame oil as a source of natural antioxidants. The impact of isolated natural antioxidants on the oxidative stability of sunflower oil during storage at ambient temperature for 8 weeks was studied . The results could be summarized in the following points: 1- Natural antioxidant content (crude lignan) was higher in Shandaweel 3 sesame oil (2.89%) as compared to Giza 32 (2.43%) and Toshka 1 (2.67%) . 2- A gradual increase in acid value occurred during storage of sunflower oils at ambient temperatures. This increment was more pronounced in oils without antioxidants than those containing natural antioxidants. 3- The iodine value decreased gradually in both oils during storage. The rate of decrement in oils without antioxidants was higher than that in oils after adding natural antioxidants. 4- The peroxide value in the stored samples tended to increase up to a maximal value, then began to decrease . Generally, the rate of peroxide formation in the samples contained natural antioxidants were lower than that of control sample during storage. 5- Increases in TBA values were higher in control sample as compared to sunflower oil that contained natural antioxidants . 6- Conjugated diene and triene contents of sunflower oils increased gradually as the storage time increased. In general it could be concluded that: 1- Sunflower oil containing natural antioxidants had a much greater oxidative stability than oils without antioxidants.In addition, natural antioxidants are safe and impart health benefits to the consumer . 2- The antioxidants are suitable in their function for increasing oxidative stability at ambient temperature only. 3- The higher efficiency of the natural antioxidants could be due to the stability of these natural antioxidants during storage.