In the title compound, [Cu(C(6)H(5)N(2)O(4))(2)], the copper(II) atom lies on an inversion centre and is in an N(2)O(2) four-coordinate environment with a nearly regular square-planar geometry. An extended network of intra-molecular O-H⋯O and inter-molecular N-H⋯O and C-H⋯O hydrogen bonds stabil-izes the crystal structure.