The structure of the title compound, (C(7)H(10)NO)(2)[Mn(2)V(10)O(28)(H(2)O)(10)].4H(2)O or (C(5)H(4)NHCH(2)CH(2)OH)(2)[{Mn(H(2)O)(5)}(2)V(10)O(28)].4H(2)O, at 293 (2) K has triclinic (P\overline{1}) symmetry. The asymmetric unit consists of one half of a decavanadate anion of C(i) symmetry, one [Mn(H(2)O)(5)](2+) group, one 2-(2-hydroxyethyl)pyridinium cation and two solvent water molecules. The decavanadate ion bridges between two [Mn(H(2)O)(5)](2+) groups, thus forming a dodecanuclear complex unit. Complex units are connected via a hydrogen-bonding network, forming supramolecular layers lying in the (001) plane. Cations and solvent water molecules are located between these layers.