In the title compound, [Tb(C(7)H(4)NO(4))(3)]·2.75H(2)O, the Tb(3+) atom is coordinated by three tridentate 6-carb-oxy-pyridine-2-carboxyl-ate ligands and lies on a crystallographic threefold rotation axis. The coordination polyhedron around Tb(III) adopts a distorted tricapped trigonal-prismatic geometry. Disordered water mol-ecules with partial occupancy are also present in the crystal, one of which is associated with each of the carboxyl-ate O atoms of the complex unit.