In the title coordination polymer, {[Gd(C(12)H(8)NO(2))(3)(H(2)O)(2)]·H(2)O}(n), the Gd(III) ion is ligated by one bidentate carboxyl-ate group, four monodentate bridging carboxyl-ate O atoms and two water mol-ecules. The resulting GdO(8) polyhedron approximates to a square anti-prism. The bridging ligands link the metal ions into a [100] chain, with each pair of adjacent metal ions being bridged by two ligands. Inter-chain O-H⋯O and O-H⋯N hydrogen bonds help to establish the packing.