The thermal decomposition of alpha-tetralyl hydroperoxide (THPO) has been investigated under a variety of conditions : in dynamic (argon and air) atmosphere, static air and self-generated atmosphere by employing DTA and TGA methods. The decomposition of THPO proceeds in two-stages during its thermochemical degradation under non-isothermal conditions in the temperature interval from room temperature to 500-degrees-C. It has been shown that the formation of associates resulting from the proton donor-acceptor interactions affects the initial temperature of hydroperoxide decomposition. Free-radical-induced decomposition proceeds in self-generated atmosphere at 165-degrees-C. 2,6-Di-tert-butyl-4-methyl phenol at some concentrations and phenyl-alpha-naphthylamine inhibit the induced radical decomposition. The products from the THPO decomposition are identical with those obtained during its decomposition in various solvents. The DTA and TGA methods show promise as useful techniques for the investigation of free-radical induced decomposition of hydroperoxides.