The kinetics of autooxidation processes in sub-bituminous (vitrain and clarain) and high-bituminous (clarain) coal lithotypes has been calculated by the method of Coats and Redfern. The differences in the E(a) values of the thermooxidative processes show structural changes in the investigated lithotypes, Their macerallar compositions and the temperature affect the reactivity of the coal samples during oxidation by atmospheric oxygen. The results obtained suggest differences between the mechanism of the autooxidation processes occurring both in the homogeneous lithotype vitrain and in the heterogeneous clarain of equal coalification degrees, and between the clarain samples of various coalification degrees.