Oxidative dry reforming of methane has been performed for 100 h on stream using Ni supported on MgAl2O4 spinel at different loadings at 500–700 °C, CO2/CH4 molar ratio of 0.76, and variable O2/CH4 molar ratio (0.12–0.47). Syngas with an H2/CO ratio of 1.5–2.1 has been produced by manipulating reforming feed composition and temperature. The developed oxidative dry reforming process allowed high CH4 conversion at all conditions, while CO2 conversion decreased significantly with the lowering of the reforming temperature and increasing O2 concentration. When considering both greenhouse gas conversions and H2/CO ratio enhancement, the optimal reforming condition should be assigned to 550 °C and O2/CH4 molar ratio of 0.47, which delivered syngas with H2/CO ratio of 1.5. Coke-free operation was also achieved, due to the combustion of surface carbon species by oxygen. The 3.4 wt% Ni/MgAl2O4 catalyst with a mean Ni nanoparticle diameter of 9.8 nm showed stable performance during oxidative dry reforming for 100 h on stream without deactivation by sintering or coke deposition. The superior activity and stability of MgAl2O4 supported Ni catalyst shown during reaction trials is consistent with characterization results from XRD, TPR, STEM, HR-STEM, XPS, and CHNS analysis. © 2019 Elsevier, reprinted with permission.