In the title compound, NH(4) (+)·(C(2)H(5)O)(2)PS(2) (-), the ammonium cation is connected by four charge-assisted N-H⋯S hydrogen bonds to four tetra-hedral O,O'-diethyl dithio-phosphate anions, forming layers parallel to (100). The polar and non-polar constituents of the layers are stacked alternately along [100]. Inter-lacing of the external ethyl groups through van der Waals inter-actions combines these layers into a three-dimensional structure.