The thermo-oxidative stability and antioxidant effectiveness of bisphenols obtained by the condensation of 2-tert-butyl-4-methylphenol with C-1-C-5 aldehydes of aliphatic series have been studied for the first time. It has been established that these features of synthesized bisphenols depend on the structure of the hydrocarbon ＇＇bridge＇＇ between the phenyl groups, and their oxidation proceeds according to the laws governing the process of Liquid-phase oxidation. It has been shown that the degradation of the investigated series of bisphenols is described by a kinetic equation with an order of the reaction of 1.25n and E-n = 74.4 kJ/mole.