In the title compound, [Cd(C10H8O4)(H2O)2)]n, the CdII cation is coordinated in a distorted trigonal–prismatic fashion. 3-(4-Carboxyphenyl)propionate (cpp) ligands connect the CdII cations into zigzag [Cd(cpp)(H2O)2)]n coordination polymer chains, which are oriented parallel to [101]. The chains aggregate into supramolecular layers oriented parallel to (10\overline{1}) by means of O—H...O hydrogen bonding between bound water molecules and ligating cpp carboxylate O atoms. The layers stack in an ABAB pattern along [100] via other O—H...O hydrogen-bonding mechanisms also involving the bound water molecules. The crystal studied was an inversion twin.
