Ceria-promoted nickel catalysts supported on nanocrystalline MgO were prepared and employed in methane reforming with CO2. Their characterization was accomplished by X-ray diffraction, BET, temperature-programmed oxidation, and temperature-programmed reduction (TPR) techniques. Cerium oxide (CeO2) proved to have a positive effect on catalytic activity, stability, and carbon suppression in methane reforming with CO2. A higher CeO2 content increased the catalyst activity and decreased the amount of deposited carbon over the spent catalysts. The suppression of carbon was related to the high oxygen storage capacity of CeO2. In addition, TPR analysis revealed that the CeO2 promoter reduced the chemical interaction between nickel and support, resulting in an increase in reducibility and higher dispersion of nickel.