Abstract: A study was conducted to find out the best ratio of 3 types of oil [sunflower oil, corn oil and refined, bleached and deodorized palm olein (RBD palm olein)] that is more stable during frying. In this study 6 different ratios, including 1) 100% RBD palm olein, 2) 100% sunflower oil, 3) 100% corn oil, 4) combination of sunflower oil and RBD palm olein (50:50), 5) combination of corn and RBD palm olein (50:50), 6) combination of sunflower and corn oil (50:50) were used to evaluate the oils performance under deep frying conditions. The chemical characteristics of these oils were evaluated by free fatty acids, iodine value and peroxide value. Changes in the above values of the oils were also examined after their use for deep-frying of potato chips at 180°C. Results showed that the iodine value decreased significantly (p<0.05) with increased replication time of frying, whereas Peroxide value and free fatty acid increased up.