The thermal decomposition of sulfates of iron(III), cobalt, nickel, copper and zinc was kinetically studied in flowing nitrogen by use of a thermobalance. Disk-like pellets compacting the anhydrous sulfate powders were used. The decomposition occurred at the phase boundary between the undecomposed sulfate and the oxide product, and the boundary proceeded uniformly from the surface towards the interior. The thickness, x, of the oxide product layer was proportional to the time, t, for Fe 2(SO 4) 3, CoSO 4 and NiSO 4. The x vs. t curves for CuSO 4 and ZnSO 4 were shown to become two straight lines with a break point. This is due to the formation of their oxysulfate as the intermediate. The In k vs. 1/ T relationship moves from lower to higher temperatures in the order: Fe 2(SO 4) 3, CuSO 4, CoSO 4, NiSO 4, ZnSO 4. The activation energies of the decomposition for sulfates of iron(III), cobalt, nickel, copper and zinc were 212, 217, 257, 211 and 238 kJ mol −1, and those for oxysulfates of copper and zinc at the later stage of the decomposition were 221 and 275 kJ mol −1, respectively. The activation energies were closely related to the enthalpies of decomposition for the sulfates.