Thermal gravimetric analysis, and differential thermal behaviour of unoxidized and oxidized starch were studied. Degradation was found to be first order in sample weight reaction. The activation energy values and the rate constants were calculated from the kinetic of weight loss. Unoxidized starch was found to be less stable than oxidized starch and the stability of the samples was arranged in the order of oxidized starch with 8 g active Cl/l > 4 g active Cl/l > 6 g active Cl/l > unoxidized starch. Volatilization and activation energies of oxidized starch were higher than unoxidized starch. DTA of unoxidized and oxidized starch show that the degradation is exothermic.