The title complex, [Cu(SO(4))(C(6)H(8)N(2))(2)]·H(2)O, was obtained under hydro-thermal conditions. The Cu(II) ion is five-coordinated in a distorted square-pyramidal manner by four N atoms from two benzene-1,2-diamine ligands at the base and one O atom from a monodentate sulfate anion at the apex of the coordination polyhedron. N-H⋯O hydrogen bonding between the amino functions and the sulfate groups leads to the formation of layers parallel to (001). C-H⋯O hydrogen bonding inter-actions between the layers consolidate the three-dimensional set-up. There are voids in the structure filled with lattice water mol-ecules that are disordered over three sites in a 0.430 (6):0.270 (6):0.300 (6) ratio.