In the structure of the title compound, [Cu(II)(en)(2)][(EtO)(2)P(S)S](2) (en is ethylenediamine) or [Cu(C(2)H(8)N(2))(2)](C(4)H(10)O(2)PS(2))(2), the Cu atom lies on a center of inversion and is coordinated in a slightly distorted square coordination geometry by four N atoms from two ethylenediamine molecules. The diethyl dithiophosphate moieties, (EtO)(2)P(S)S(-), act as counter-anions.