Abstract: Four different used tire samples were pyrolysed in a TG/DTA analyzer under N2. The tire samples showed two distinct weight losses in TG/DTG profiles, representing decomposition at a lower and a higher temperature. The major rubber ingredients of the tires, natural rubber (NR), styrene -butadiene rubber (SBR) and polybutadiene rubber (BR), were pyrolysed separately under the same conditions. NR decomposed mainly at a lower temperature, SBR and BR at a higher temperature. In addition, different heating rates affected the shape of DTG curves in tire samples pyrolysis. It was found that tires and rubber ingredients pyrolysis can be described by 1st order kinetics. The kinetic parameters (pre - exponential factor and apparent activation energy) were determined in Arrhenius plots with two linear regions. Also, tire samples composition was obtained by using TGA, in general, 6% - 9% volatile matters, 55% - 60% rubber, 30% - 33% carbon black, and 3% - 6% ash. The DTA results showed that the pyrolysis of tires is an exothermic process which may result from synthetic rubber depolymerization and natural rubber pyrolysis weight loss.