The pyrolysis kinetics of commercial-grade styrene-butadiene rubber (SBR), which is one of the major constituents of tyre rubber as well as one of the principal products of the rubber industry in Taiwan, was investigated by a dynamic thermogravimetry (TG) reaction system in a nitrogen atmosphere over the temperature range of 400 to 950 K at the nominal heating rates of 3, 5 and 7 K min(-1). The experimental results indicated that the pyrolysis of SBR may be attributed to three reactions, with three distinct mass change characteristics in the mass-loss curves of reactant deduced from the experiments. The corresponding activation energies, frequency factors and reaction orders of the three reactions were determined. A simplified three-reaction model based on the mass-loss curves of reactant was also proposed for engineering purposes. Satisfactory agreements between the proposed model and the experimental results were obtained. The results of this study are useful for the utilization of scrap SBR as an energy resource.