Both mol-ecules of the title compound, [Ni(C(2)O(4))(C(16)H(36)N(4))]·C(2)H(2)O(4), are located on a crystallographic twofold rotation axis. The Ni(II) atom shows a distorted octa-hedral geometry. The crystal packing is stabilized by N-H⋯O and O-H⋯O hydrogen bonds.