In the title compound, [Ni(C8H3NO6)(C10H8N2)(H2O)3]·H2O, the NiII cation is six-coordinated by a chelating 2,2′-bipyridine ligand, one carboxylate O atom from a 5-nitroisophthalate dianion and three water molecules, with a slightly distorted cis-NiN2O4 octahedral geometry. The neutral complex is isolated, in contrast to coordination polymers formed by MnII, CoII and CuII with the same ligand set, but forms an extensive network of O—H⋯O hydrogen bonds between the coordinated and uncoordinated water molecules and carboxylate groups of the 5-nitroisophthalate ions.