The thermal decompositions of tetralin and of alpha- tetralyl hydroperoxide (THPO) in the presence of tetralin have been investigated in the temperature range 23-500 degrees C by employing DTA and TGA. The thermochemical decomposition of tetralin is a one-stage process in the temperature range 65-180 degrees C under non-isothermal conditions. It was shown that tetralin retards the thermal decomposition of THPO due to the decrease of the steady-state concentration of tetralyl radicals and its participation in the radical decomposition. The formation and decomposition of the intermolecular (OH...pi) associates between THPO and the tetralin molecule influence the hydroperoxide homolysis and the initial temperature of the decomposition. The presence of gamma-o-hydroxyphenyl butyric acid, a natural inhibitor of the studied systems, was observed. The presence of bitetralyl peroxide and bitetralyl ether in the reaction product at 160 degrees C indicates that termination reactions take place with the dominating participation of tetralyl radicals. The presence of bitetralyl tetroxide indicates a probable gas-phase mechanism in non-isothermal conditions and decreased oxygen access.