The kinetic parameters of the thermal decomposition of magnesite were investigated using TGA data. For the kinetic analysis, the Coats-Redfern and Suzuki methods were separately applied. It was observed that the process fitted a first-order kinetic model and the values of the activation energies decreased with decreasing particle size, which can be attributed to the increasing particle internal resistance to the escape Of CO2 as the grain size increased. According to Coats-Redfern and Suzuki methods, the activation energy values were found to be 236.25-278.37 and 255.52-302.21 kJ mol(-1), respectively, for the range of particle size fraction used.