In the title compound, {[NiTb2(C14H8N2O5)4(H2O)4]·4H2O} n , the Tb(III) ion is coordinated by one water mol-ecule and seven O atoms from four 5-(pyridine-4-carboxamido)-isophthalate (L) ligands in a distorted square-anti-prismatic arrangement, while the Ni(II) ion, lying on an inversion center, is six-coordinated in an octa-hedral geometry by two pyridine N atoms, two carboxyl-ate O atoms and two water mol-ecules. One L ligand bridges two Tb(III) ions and one Ni(II) ion through two carboxyl-ate groups and one pyridine N atom. The other L ligand bridges two Tb(III) ions and one Ni(II) ion through two carboxyl-ate groups, while the uncoordinating pyridine N atom is hydrogen bonded to an adjacent coordinating water mol-ecule. Extensive O-H⋯O, N-H⋯O and O-H⋯N hydrogen bonds play an important role in stabilizing the crystal structure.