In the centrosymmetric title molecule, [Mn(2)(C(6)H(2)O(8))(H(2)O)(8)], the Mn(II) atom is in an octa-hedral environment coordinated by six O-atom donors from water mol-ecules and ethane-1,1,2,2-tetra-carboxyl-ate ligands. The crystal structure features a three-dimensional hydrogen-bonding network based on a strong and distinctive pattern of O-H⋯O hydrogen-bonding inter-actions.