In the title polymer, {[Cu(SO(4))(C(12)H(9)N(3)O)(2)(H(2)O)(2)]·4H(2)O}(n), both the metal center and the sulfate anion are located on a twofold axis. The Cu(II) ion is coordinated by two pyridyl N atoms from two symmetry-related organic ligands, two O atoms from two symmetry-related water mol-ecules, and two O atoms from two symmetry-related sulfate anions, resulting in a distorted octa-hedral geometry. The sulfate anions act as μ(2)-bridges and connect metal ions, forming a one-dimensional chain along the b axis. The three-dimensional crystal structure is established through inter-molecular N-H⋯O and O-H⋯O hydrogen bonds involving the organic ligands, sulfate anions, coordinated and uncoordinated water mol-ecules, and through π-π inter-acting 2-pyridone rings, with centroid-centroid separations of ca 3.96 Å and tilt angles of ca 2.62°.