Tocopherols are important lipid-phase antioxidants that are subject to heat degradation. Therefore, kinetic analyses for oxidative degradation of tocopherols as a function of temperatures and times were performed. Alpha-, gamma- and delta-tocopherols dissolved in glycerol were heated at 100${sim}$250$^{circ}C$ for 5～60 min. Oxidized tocopherols were analyzed by HPLC using a reversed phase ${mu}$-Bondapak C$_{18}$-column with two kinds of elution solvent systems in a gradient mode. The degradation kinetics for tocopherols followed a first-order kinetic model. The rate of tocopherol degradation was dependent on heating temperatures. The degradation rate constants for ${gamma}$- and ${delta}$-tocopherols were higher than those for ${alpha}$-tocopherol. The experimental activation energies of ${alpha}$-, ${gamma}$- and ${delta}$- tocopherols were 2.51, 6.05 and 5.34 kcal/mole, respectively. The experimental activation energies for the oxidative degradation of ${gamma}$- and ${delta}$-tocopherols were higher than that of ${alpha}$-tocopherol.