The title compound, [NH(3)(CH(2))(2)NH(3)][Mg(SO(4))(2)(H(2)O)(4)], was synthesized by the slow evaporation method. Its crystal structure can be described as an alternate stacking of inorganic layers of tetra-aqua-bis(sulfato-O)magnesium [Mg(SO(4))(2)(H(2)O)(4)](2-) anions ( symmetry) and organic layers of [NH(3)(CH(2))(2)NH(3)](2+) cations along the crystallographic b axis. The anions, built up from tetrahedral SO(4) units and octahedral Mg(H(2)O)(4)O(2) units, and the cations are linked together through N-H⋯O hydrogen bonds, forming a three-dimensional network. O-H⋯O inter-actions are also present.