Abstract Hydrotalcite-type materials with different Ni:Mg:Al ratios have been prepared and characterized by different methods (powder X-ray diffraction, differential thermal analysis and thermogravimetric analysis, FT-IR and VIS–UV/diffuse reflectance spectroscopies and specific surface area and pore size distribution assessment). Samples calcined at 600°C, where the layered structure has been destroyed, are formed by non-stoichiometric NiO–MgO oxides, and their catalytic activity in n -butane and propene oxidative dehydrogenation has been studied; production of methane and ethylene, in addition to CO 2 and H 2 O, is observed. The sample without Ni is not active in these reactions, but, among those containing Ni, that with the lowest content exhibits the largest activity.