The title compound, {[CoBr(2)(C(5)H(4)N(2)O(2))(H(2)O)]·H(2)O}(n), is a one-dimensional coordination polymer which crystallizes as a monohydrate. The asymmetric unit contains one Co(II) atom in a distorted octa-hedral geometry, forming a chain parallel to [010] with the pyrazine carb-oxy-lic acid ligands coordinating on one side in a bidentate fashion through one N and one O atom, and in a monodentate fashion through a N atom, with N atoms trans, and with both ligands lying in the same plane. The bromide atoms are cis to each other, while a water mol-ecule occupies the final octa-hedral coordination site. The chains are linked together though an O-H⋯Br hydrogen bonding network, and are further stabilized by an O-H⋯Br and O-H⋯O hydrogen-bonding framework with the solvent water mol-ecule.