Nickel catalysts supported on BeO, MgO, ZnO, Al2O3, Cr2O3, SiO2, TiO2, ZrO2, ThO2, and UO2, with different metal loading, have been prepared by coprecipitation or by impregnation of the basic nickel carbonate with a water solution of nitrate of the support. Metal surface areas were measured by hydrogen chemisorption. The activity of the catalysts have been determined under flow conditions, at atmospheric pressure, for the deuterium exchange reaction between ammonia and hydrogen. The reaction rates normalised to metal surface area are strongly affected by the nature of the support. Generally, the presence of the support enhances the intrinsic activity of catalyst compared to that of the nickel black; the highest increase is shown by TiO2 (ca. 800-fold). The results emphasize the importance of the support in the enhancement of the catalytic activity for the deuterium exchange reaction between hydrogen and ammonia. It is assumed that the role of the support is to create new active sites at the interface between the metal and the support, either through a direct or an indirect involvement of the support in activation of the ammonia molecule.