The decomposition of tyre wastes at different heating rates in an oxidizing atmosphere is explained by means of a kinetic model including a first step of pyrolysis, which assumes three organic fractions not forming residues, and a step of combustion. The atmosphere used varied from 10 of oxygen to 20% (v/v). The activation energy for the step of combustion is in the range 221-235 kJ/mol, and there exists a dependence of the rate of decomposition on the partial pressure of oxygen.