Crystals of manganese(II) dibarium bis-(hydrogenphosphate) bis-(dihydrogenphosphate), MnBa(2)(HPO(4))(2)(H(2)PO(4))(2), were obtained by hydro-thermal synthesis. The title compound is isotypic with its Cd(II) and Ca(II) analogues. The structure is built up of an infinite {[Mn(HPO(4))(2)(H(2)PO(4))(2)](4-)}(n) chain running along [100], which consists of alternate MnO(6) octa-hedra and [PO(4)] tetra-hedra, in which the centrosymmetric MnO(6) octa-hedra share their four equatorial O-atom corners with tetra-hedral [PO(3)(OH)] groups and their two axial apices with tetra-hedral [PO(2)(OH)(2)] groups. These chains are held together by BaO(9) coordination polyhedra, developing into a three-dimensional structure. The O-H⋯O hydrogen bonds additionally stabilize the structural set-up. Due to the ionic radius of Mn(2+) being much smaller than those of Ca(2+) and Cd(2+), this may imply that their adopted structure type has a great tolerance for incorporating various ions and the exploitation of more diverse compounds in the future is encouraged.