In the title compound, [Pb₂(C₇H₄O₆S)₂(C₁₂H₈N₂)₂(H₂O)₂]·CH₃COOH, the seven-coordinate Pb(II) atom is chelated by two N atoms of one 1,10-phenanthroline ligand, four O atoms from three 5-sulfosalicylate dianions and one water O atom. Each dianion serves as a bridging ligand, connecting adjacent Pb(II) atoms into a centrosymmetric polymeric chain extending parallel to [001]. There are π-π inter-actions between the aromatic systems of neighbouring dianions, with plane-to-plane distances of 3.371 (2) Å, and between phenanthroline ligands, with a centroid-to-centroid distance of 3.484 (2) Å. O-H⋯O hydrogen bonding additionally stabilizes the crystal packing. The acetic acid mol-ecules are incorporated in the voids of this arrangement. They exhibit half-occupancy due to disorder around a centre of inversion.