The antioxidant activity of pomelo peels was evaluated with different organic solvents. Minimum yield (11.1%) was obtained with chloroform +methanol (2:1), maximum yield (21.6%) with methanol whereas (15.9%) with ethanol and (12.7%) with hexane were observed. The maximum scavenging activity of (ethanolic pomelo peel extract) 88.8 % was observed at 14mg/ml concentration. Antioxidant activity of ethanolic pomelo peel extract was evaluated by calculating free fatty acid, iodine value and p-Anisidine value of peanut oil during 21 days of storage period at room temperature. Samples were drawn and analyze periodically after 7 days and after 21 days of storage, peanut oil containing 1500 and 2000 ppm pomelo peel extract, be revealed lower free fatty acid values (2.66, 2.15%), and p- anisidine value (6.6, 4.68) and higher iodine value (52.8, 51.46) than control peanut oil sample (free fatty acid 9.32%, p- anisidine value 9.85 and iodine value 33.9). From the results, it could be concluded that natural antioxidants extracted from pomelo peel could be added to fat and oil to increase their shelf life by preventing oxidative rancidity.