The thermal decomposition of -irradiated KClO3 was studied by dynamic thermogravimetry. The reaction order, activation energy, frequency factor and entropy of activation were computed using the Coats-Redfern, Freeman-Carroll and Horowitz-Metzger methods and were compared with those of the unirradiated salt. The decomposition increases with the irradiation dose. The energy of activation decreases on irradiation. The mechanism for the decomposition of unirradiated and irradiated KClO3 follows the Avrami model equation, 1-(1-)1/3, and the rate controlling process is a phase boundary reaction assuming spherical symmetry.