In title compound, [Ni(C(9)H(5)NO(4)S)(H(2)O)(2)](n), the Ni(II) atom is coordinated by one N atom and two bridging O atoms from two 8-oxidoquinoline-5-sulfonate ligands, one sulfonate O atom from a third ligand, and two water mol-ecules in a distorted octa-hedral geometry. The two Ni(II) atoms are linked to each other through the bridging O atoms, forming a dimer. Adjacent dimers are connected through the coordination of the sulfonate O atom into a two-dimensional coordination network parallel to (010). Hydrogen bonds between the coordinated water mol-ecules and the uncoordinated O atoms of the sulfonate groups result in the construction of a three-dimensional supra-molecular structure.