Gd₃NiSi₂ annealed sample has been investigated by magnetization, electrical resistivity and specific heat measurements. This study reveals its ferromagnetic behavior below T_C = 215 K; only the gadolinium carries a magnetic moment with a saturation magnetization of 7.19 μ_B/Gd mol. Gd₃NiSi₂ exhibits a magnetocaloric effect higher in magnetic entropy change than the one recently reported for Gd₆Ni_5/3Si₃. This ternary silicide can be obtained as metallic ribbons where the structural disordering modifies strongly its magnetocaloric properties.