In the title compound, [Co(C(11)H(8)N(5)O)Cl](n), the Co(II) atom is penta-coordinated by one O atom and two N atoms from a 5-(8-quinolyloxymeth-yl)tetra-zolate ligand, one N atom from another symmetry-related ligand, and a Cl atom. The coordination geometry can be described as slightly distorted trigonal-bipyramidal. Adjacent Co atoms are connected by the bridging tetra-zole groups into a chain. The dihedral angle between the quinoline and tetra-zole planes is 21.2 (1)°. The structure involves intra- and inter-chain C-H⋯N hydrogen bonds.