...Soybean oil is the most consumed oil worldwide due to its cheapness but presented aweak thermo-resistance due to its richness in poly-unsaturated fatty acids. This studyaims to improve the thermo-stability of refined soybean oil by blending it with somecold-pressed oils. For this, cold-pressed and soybean oils were firstly characterized(K232, K270, acidity, peroxide value, iodine value, induction time, phenolic contents,and antioxidant activity). Then, binary blends of each cold-pressed oil (30%) withsoybean oil (70%) were analyzed before and after heat treatment (170°C for 10h/dayfor 5 days) followed by the application of the simplex lattice mixture design in order tooptimize the combination of the three best cold-pressed oils. The changes in fatty acidprofiles were assessed by gas chromatography (GC-FID). The results revealed thatsoybean oil presented the best physicochemical traits, while cold-pressed oils expressed high levels of phenolic contents and antioxidant activities. From the sixbinary oil blends, soybean oil mixed with lentisk, sesame, or almond oils were selectedfor their best thermo-stability. The simplex lattice mixture design, applied for thesethree chosen oils, indicated that the combination of soybean oil (70%) with lentisk andsesame oils (17.7 and 12.3%, respectively) was considered the optimal blend thatgives the maximal thermo-stability improvement to soybean oil. GC-FID analysis showed that fatty acids, particularly linoleic and linolenic acids, were more conservedafter heat-treatment in optimal oils blend than soybean oil. This study clearly demonstrated that lentisk and sesame oils enhanced the thermo-resistance of soybean oil, and the findings of this study could be used as an integrated model in oil and fatindustries