The title complex, [Co2(C8H5NO4S)2(C10H8N2)3(H2O)2]·1.3H2O, was synthesized under hydro-thermal conditions. The Co(II) ion is six-coordinated in a slightly distorted octa-hedral environment resulting from two carboxyl-ate O atoms of two 2-carb-oxy-methyl-sulfanyl nicotinate (2-CMSN(2-)) anions, one water mol-ecule and three N atoms of three 4,4'-bi-pyridine ligands, with one 4,4'-bi-pyridine ligand situated on a centre of inversion. Two neighboring Co(II) ions are linked by two anions, giving a dinuclear [Co2(2-CMSN)2] subunit with a Co⋯Co separation of 6.8600 (3) Å. The dinuclear subunits are joined by bridging 4,4'-bi-pyridine linkers, generating a three-dimensional network structure. Disordered water mol-ecules are situated in the free space of this network. O-H⋯O hydrogen bonding within and between the subunits enhances the stability of the structure.