In the crystal structure of the polymeric title compound, [Co(μ-C8H4O4)(CH3OH)2(H2O)2]n, two independent CoII atoms both occupy special positions with \overline{1} site symmetry. Each CoII atom assumes a distorted octahedral coordination geometry. The phthalate anion acts as a bridging ligand and leads to the formation of a zigzag chain running along the c axis. O—H⋯O and C—H⋯O hydrogen bonds connect the chains and result in the formation of a three-dimensional structure.