In the trinucler Cu(II) complex mol-ecule of the title compound, [Cu(3)(C(5)HN(2)O(4))(2)(H(2)O)(8)]·4H(2)O, the central Cu(II) atom is located on an inversion centre and is coordinated in a distorted octa-hedral geometry. The equatorial sites are occupied by two N and two O atoms from two pyrazole-3,5-dicarboxyl-ate ligands and the axial positions are occupied by two water mol-ecules. The two other symmetry-related Cu(II) atoms are penta-coordinated and assume a square-pyramidal geometry. In the crystal structure, coordinated and uncoordinated water mol-ecules and carboxyl-ate O atoms are linked by O-H⋯O hydrogen bonds.