The title compound, (C12H16N3O)[PtCl4]Cl, consists of a 4,4'-(1-aza-niumyl-2-hy-droxy-ethane-1,2-di-yl)dipyridinium trication, a square-planar tetra-chloridoplatinate(II) dianion and a chloride ion. In the cation, the pyridinium rings attached to the central 1-aza-niumyl-2-hy-droxy-ethane fragment have an anti conformation, as indicated by the central C-C-C-C torsion angle of -166.5 (6)°, and they are inclined to one another by 63.5 (4)°. In the crystal, the cations and anions are linked through N-H⋯Cl and O-H⋯Cl hydrogen bonds. There are also π-π contacts [centroid-centroid distances = 3.671 (4) and 3.851 (4) Å] and a number of C-H⋯Cl inter-actions present, consolidating the formation of a three-dimensional supra-molecular structure.