The title compound, [Mn(C 12H 9N 2O 2S) 2(H 2O) 4]·2H 2O, has been synthesized with a flexible asymmetrical bridging ligand, 4-(pyrazin-2-ylsulfanylmethyl)benzoic acid (Hpztmb). The Mn II ion exhibits a centrosymmetric octahedral geometry involving two carboxylate O atoms of two different pztmb ligands and four O atoms of four coordinated water molecules. The packing shows a three-dimensional supramolecular network via O—H⋯O and O—H⋯N hydrogen bonds and π–π stacking interactions [centroid–centroid distances = 3.884 (8) and 4.034 (8) Å] between the benzene ring of one pztmb anion and the pyrazine ring of an adjacent anion.