In the title linear coordination polymer, [Zn(C(6)H(4)N(2)O(4)S(3))(H(2)O)(4)](n), the Zn(II) atom is coordinated by four O atoms from four water mol-ecules and two O atoms from two [5-(carb-oxyl-atomethyl-sulfan-yl)-1,3,4-thia-diazol-2-ylsulfan-yl]acetate units in an octa-hedral coordination environment. The chains are linked into a three-dimensional supra-molecular network via O-H⋯O and O-H⋯N hydrogen bonds.