Nitrous oxide (N2O) was recognized as a strong greenhouse gas that can be reduced by applying post-treatment technologies. N2O catalytic decomposition is considered the most attractive method for N2O abatement due to its easy operation and high efficiency. Among several catalysts, the cobalt-based mixed oxides have been identified as the most performing for this reaction. In this work a NixCo3-xO4 catalyst was prepared, characterized by means of nitrogen physisorption, X-ray diffraction (XRD), scanning electron microscopy (SEM), and X-ray fluorescence spectroscopy (XRF), and tested in the N2O decomposition reaction in presence of two different reactant mixtures, by using N2O and O2 with two different vol% as reactants, in order to evaluate the effect of the latter on the catalytic behavior. The results demonstrated that the concentrations of N2O and O2 in the gaseous stream strongly influenced the activity of the catalyst, indeed, by halving the O2 concentration, the N2O conversion increases from 54 % to 79 %. The NixCo3-xO4 sample resulted a promising catalyst for N2O decomposition reaction of gaseous stream containing up to 5 vol% of N2O, also in presence of O2.