Thermogravimetry was used to follow the oxidation-reduction as well as the regeneration processes of deactivated NiO/gamma-Al2O3 catalysts. The results indicate that the catalysts, whose deactivation was caused bg the sintering of metallic Ni and by the forming of NiAl2O4 species, could be regenerated through a reduction-oxidation method. Especially, the regeneration of NiAl2O4 to NiO was more than 90%.