The effects of 400 ppm ascorbyl palmitate (AP) on fatty acids composition, tocopherol, peroxide value (PV) and malonaldehyde (MAD) contents of refined cottonseed oil (CO) and virgin olive oil (OO) during chemical interesterification (CI), and storage at 60 degrees C for 28 days were investigated. CI significantly decreased (p<0.05) the tocopherol contents of CO and OO. PVs and MAD contents of oil samples considerably increased up to 20 min of CI, followed by a reduction at 30 min. The unsaturated fatty acids/saturated fatty acids (UFA/SFA) ratios of the samples showed slight but significant (p<0.05) reduction during accelerated oxidation process. Oils with added 400 ppm AP had higher tocopherol, and lower PVs and MAD contents than their counterparts without AP during CI, and storage at 60 degrees C. AP increased the oxidative stability of interesterified and non-interesterified CO and OO.