In the title coordination polymer, [Ba(1,3-BDOA)(H2O)2]n (where 1,3-BDOA2- is the m-phenylenedioxydiacetate dianion, C10H8O6), each Ba(II) ion is ten-coordinated by six carboxyl O atoms and two ether O atoms from different 1,3-BDOA(2-) ligands, as well as by two water molecules, thus defining a dodecahedron. The Ba(II) atoms are covalently linked by 1,3-BDOA2- ligands in different crystallographic directions, giving rise to a three-dimensional open framework. The crystal structure is further stabilized by hydrogen bonds and pi-pi stacking interactions. In previously studied polymers of this type, the 1,3-BDOA2- ligand showed multiple bridging modes with metal ions, including bi-, tri-, tetra- and hexadentate. The title Ba(II) complex represents a novel three-dimensional coordination polymer constructed by octadentate bridging 1,3-BDOA2- ligands.