A group of Ni/Al2O3 catalysts having metal contents in the 0-16.5 wt% range were prepared using coprecipitation and impregnation methods. The catalysts were reduced under the same conditions; the reaction conditions were also fixed in similar sets of experiments for better comparison, Total surface area, total pore volume, metal surface area, and both the CO hydrogenation and CO2 methanation activities of the catalysts were studied in order to compare the effect of preparation method on structural properties as well as on catalyst activity and selectivity. A comparison of CO hydrogenation results on catalysts with similar nickel loadings indicates that coprecipitated catalysts have higher productivity and C-2-C-4 hydrocarbon selectivity, whereas impregnated catalysts yield better olefin/paraffin ratios for the C-2-C-3 hydrocarbons. In CO2 methanation, coprecipitated catalysts show higher methanation activity and lower CO production level per methane produced for all nickel loadings investigated.