In the present work, a group of nickel-ceria nanocatalysts was synthesized by co-precipitation method and their catalytic performances were considered in CO methanation reaction. The catalysts were characterized by XRD, BET, SEM, TEM, H-2-TPR, CO chemisorption and CO-TPD techniques. The results showed that addition of nickel content up to 50 wt.% increased both the CO conversion and CH4 selectivity at low temperatures while further increase in nickel content adversely affected them. The 50%Ni/CeO2 catalyst revealed an excellent activity in CO methanation due to high surface area (258 m(2)/g), small nickel particle size (below 5 nm) and high metal dispersion (7.31%). In CO selective methanation, CO2 conversion was completely suppressed until CO conversion reached to a maximum value, which is an important factor from commercial view point where is needed to extend operating temperature window between maximum of CO conversion and suppressing of CO2 methanation. Copyright (C) 2015, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.