An approach developed earlier to the investigation of processes of oxidation of complex multicomponent systems has been extended to a form of hydrocarbon materials of practical importance-lubricating oils. The kinetic mechanisms of oxidation of base oil based on isoparaffinic hydrocarbons at 120-160-degrees-C have been studied. A mathematical model of the process investigated has been obtained. This consists of a system of equations with nine kinetic parameters characterizing the properties of the initial substrate, hydroperoxides and impurity inhibitor. The mathematical model quantitatively describes available experimental data and characterizes specific features of the oxidation of isoparaffinic oil under the conditions examined.