Two Ni-MgO systems were synthesized and characterized as nickel catalysts for the hydrogenation of 1,6-hexanedinitrile (adiponitrile) in the gas phase. The activity results were compared with those obtained for a commercial Raney-Ni. All three catalysts showed high selectivity to 1,6-hexanediamine, for a total conversion with a maximum of 96% for the Ni-MgO catalyst, which was made from a NiO-MgO solution. However, only Ni-MgO catalysts showed high selectivity to 6-aminohexanenitrile (83 and 77%, respectively) and high conversion (87 and 85%, respectively). The higher selectivity to 6-aminohexanenitrile could be related to the presence of octahedral crystallites in the Ni-MgO catalysts.