Catalytic decomposition of nitrous oxide to nitrogen and oxygen has been carried out on "in situ" generated thermally calcined hydrotalcites of the general formula M-Al-CO3-HT, where M stand for Ni, Co and Cu, in the temperature range 140-310-degrees-C at 50 Torr (1 Torr= 133.3 Pa) initial pressure of the gas. All the catalysts showed first-order dependence on nitrous oxide without any inhibition by oxygen. Among the catalysts studied, Ni-Al-CO3-HT was the most active, followed by the cobalt and copper catalysts. These catalysts are more active in comparison with earlier reported Cu-ZSM-5, Co-ZSM-5 and Rh-ZSM-5 catalysts based on their conversion for the decomposition. The enhanced activity can be attributed to non-stoichiometry and dispersion of the active mixed metal oxides. Prior to the kinetic runs, the catalytic precursors were characterised by X-ray diffraction, thermogravimetry-differential scanning calorimetry measurements, IR, transmission electron microscopy and nitrogen adsorption measurements.