The influence of zinc addition on the catalytic performance and physicochemical properties of nickel-based catalysts used in selective hydrogenation of acetylene was investigated. It was found that the activity and selectivity to ethylene of the nickel-based catalysts were positively modified by incorporation of zinc into their solid structure. The zinc-modified catalysts produced smaller amounts of coke and methane than those not containing zinc. Coke deposition had a strong effect on the ethylene selectivity. However, this influence was much more significant for zinc-modified catalysts than for nonmodified nickel-based solids. These results were explained taking into account the different crystalline structures obtained for both types of solid. In the case of zinc-modified catalysts, the metal nickel phase was interacting strongly and highly interdispersed in a nonstoichiometric zinc aluminate spinel matrix. The high interdispersion of the metal nickel phase diminished the number of three-nickel-atom arrangements necessary for the formation of surface intermediates that led to coke and methane production. The nonmodified nickel-based solids, however, were composed of large metal crystallites on which coke and methane precursors were very easily formed. The high interaction between metal nickel particles and the zinc aluminate matrix prevented whisker formation to some extent. Finally, the low concentration of acid sites on the solid surface considerably reduced amorphous-like coke deposition.