The crystal structure determination of the title compound, [Cu(C4H12N2)(2)(H2O)(2)](C4O4), is reported. It adopts an elongated octahedral trans-[CuN4O2] coordination geometry with the Cu-II atom located at a centre of symmetry. The axial Cu - O bond length is 2.6066 (17) Angstrom, while the equatorial Cu - N bond lengths are 1.9849 (16) and 2.1102 (16) Angstrom. Intermolecular O - H ... O and N - H ... O hydrogen bonds are responsible for linking the complex cation to the squarate dianion, forming layers. The anion is also centrosymmetric.