The title compound, [Co(C10H8N2)3]2[V4O12]·11H2O, is composed of two symmetry-related cations containing octahedrally coordinated CoII ions, a centrosymmetric [V4O12]4− anion with an eight-membered ring structure made up of four VO4 tetrahedra, and 11 solvent water molecules. The CoII cations and vanadate anions are isolated and build cation and anion layers, respectively. In addition, the title compound exhibits a three-dimensional network through intra- and intermolecular hydrogen-bond interactions between water molecules and O atoms of the anions, and the crystal structure is stabilized mainly by hydrogen bonds.