This study was performed to evaluate the effect of guava seeds (GVSE) and grape seeds (GRSE) extracts compared to butylated hydroxytoluene (BHT) on the antioxidant activity of blended sunflower and soybean oils (1:1 V/V), defined as BO at 70^oC for 72 hrs. GVSE and GRSE were separately added to the blended oils at two different concentrations (200 and 500 ppm). Synthetic antioxidant BHT at ratio of 200 ppm was used as positive control with the blends oils. The oxidative assessments were Peroxide value, P- anisidine value, total oxidation value and thiobarbituric acid reactive substances were used for measuring the oxidative stability of these blended oils. Results showed that the highest level of GVSE and GRSE gave the best protection against primary and secondary oxidation of blended oil samples. The high efficiency of these extracts was observed as follows: 500 ppm GRSE ˃ 500 ppm GVSE ˃ 200 ppm BHT ˃ 200 ppm GRSE ˃ 200 ppm GVSE ˃ control. Therefore, some of food processing wastes could be used as natural antioxidant in edible oils manufacturing.