The crystal structure of the title compound, {[Fe(C(6)H(2)N(2)O(4))(H(2)O)(2)]·2H(2)O}(n), was synthesized by a diffusion method. It has a one-dimensional polymeric chain structure and the chains are further connected into a three-dimensional structure by hydrogen bonds. The Fe(II) ion has a distorted octa-hedral coordination environment, with two N and two O atoms from the pyrazine-2,3-dicarboxyl-ate ligands in the equatorial plane and with two water mol-ecules in axial positions. The Fe atom lies on a crystallographic centre of symmetry and a twofold rotation axis passes through the pyrazine ring.