The effect of plastic deformation on the structure and properties of the ordered Cu–56Au (at.%) alloy has been studied. The deformation strain has been expressed in the cross-section area reduction (CSAR) percent from 10 to 80%. The dependences of electrical resistivity and microhardness on CSAR of both ordered and disordered alloy specimens have been plotted. Mechanical tensile tests of specimens in various structural states have also been carried out. It has been shown that after plastic deformation, the microhardness of the pre-ordered Cu–56Au alloy increases significantly and becomes higher than the microhardness of the severely deformed initially disordered alloy. It has been established that the deformation up to 70% CSAR does not cause a complete destruction of the atomic order. It has been shown that moderate plastic deformation (at 10–30% CSAR) of the ordered Cu–56Au alloy leads to obtaining of a thermal stability material exhibiting an excellent balance between high strength and low electrical resistivity. Such behavior of the alloy is attributed to the occurrence of an enriched dislocation density in the deformed ordered structure in which the deformation-induced disordered phase has not begun to form yet. © 2023 Elsevier B.V.