Second-nearest-neighbor modified embedded-atom method (2NN MEAM) interatomic potential for Cu-Co binary systems has been developed. The Cu-Co potential can be extended to Pt-Cu-Co ternary 2NN MEAM potential being combined with already existing Pt-Co potential and can be utilized for atomistic simulations to design inexpensive and efficient platinum alloy catalysts. The potential reproduces fundamental material properties such as structural and thermodynamic properties of compound and solution phases in reasonable agreement with experimental data.