Our previous work with Sibunit carbon supported nickel catalysts investigated in the reaction of 1,2-dichloroethane hydrodechlorination showed the transformation of nickel to an fcc NiCx solution and/or even to an hcp Ni3C carbide phase during reaction. Carbon entering to nickel was considered to originate from the organic molecule, not from the carbon support. To substantiate this interpretation we decided to carry out the title reaction in the presence of alumina supported nickel catalysts. Hydrodechlorination of 1,2-dichloroethane performed on differently metal loaded Ni/Al2O3 catalysts resulted in a massive carbiding of nickel, leading to the Ni3C carbide phase. This effect was better marked for the catalysts with a higher Ni loading (≥2 wt.%). However, for very high Ni loading (20 wt.%) characterized by bigger metal crystallites (~30 nm), only a portion of Ni was carbided.