Oxides such as SiO₂, γ-Al₂O₃, TiO₂(anatase and rutile), ZrO₂ and MgO with different properties have been used as supports for loading nickel by the pore volume impregnation method. Catalysts were calcined in air at 723 K for 6 h before reduction at the same temperature. Surface area and acidity measurements, X-ray diffraction and hydrogen and oxygen adsorption measurements along with hydrogenation of benzene were used as tools for characterising the catalyst. A measure of the availability of nickel in the bulk and on the surface of the catalyst is given by the O₂/H₂ ratio. In a metal–support system there is always a possibility of an interaction. The reducibility of catalysts depends on the availability of nickel ions determined by the support properties and the extent and type of interaction, and follows the order Ni/SiO₂ > Ni/TiO₂. (R)≈ Ni/ZrO₂≈ Ni/TiO₂(A) > Ni/γ-Al₂O₃ Z.Gtc Ni/MgO. The benzene hydrogenation activity was maximum around 433 K and for Ni/TiO₂(A) it occurred beyond 473 K. Easily reducible Ni/SiO₂ showed the highest activity and difficult-to-reduce Ni/MgO showed no appreciable activity. The turnover number (TON) for benzene hydrogenation is dependent on the available metal area and on the crystallite size. A smooth correlation between TON and the dispersion (S_metal//S,_B.E.T.) is observed.