In the title complex, {[Dy(C(6)H(4)NO(3))(C(2)O(4))(H(2)O)]·H(2)O}(n), the Dy(III) ion is coordinated by seven O atoms from two 2-oxidopyridinium-3-carboxylate ligands, two oxalate ligands and one water mol-ecule, displaying a distorted bicapped trigonal-prismatic geometry. The carboxyl-ate groups of the 2-oxidopyridinium-3-carboxylate and oxalate ligands link dysprosium metal centres, forming layers parallel to (100). These layers are further connected by inter-molecular O-H⋯O hydrogen-bonding inter-actions involving the coordin-ated water mol-ecules, forming a three-dimensional supra-molecular network. The uncoordinated water mol-ecule is involved in N-H⋯O and O-H⋯O hydrogen-bonding inter-actions within the layer.