In the title coordination polymer, [Ag₂(C₄H₄O₄S)], each AgI cation is four-coordinated by three of the four carboxylate O atoms and the S atom from symmetry-related sulfanediyldiacetate ligands, thus defining a distorted tetrahedral geometry at the metal centre. The AgI cations are bridged by sulfanediyldiacetate groups, leading to a two-dimensional layer structure. These layers are interconnected via Ag-S bonds to form a three-dimensional coordination polymer network overall.