Systems consisting of metallic layers are commonly used in many applications for microelectronics, data storage, protection coatings, and microelectromechanical systems. The physical properties of such systems are strongly determined by the flow of the electron and phonon gases and their interactions. In this study, the effective thermal conductivity of a metal-metal bilayer system is studied using the two-temperature model of heat conduction. By defining the total interfacial thermal resistance, it is shown that the thermal conductivity of the bilayer system depends on the ratio between the thicknesses of the metallic layers and their intrinsic coupling length and it has a simple interpretation as the sum of thermal resistances in series. It is demonstrated that the total interfacial thermal resistance can be minimized by choosing appropriately the thermal and geometrical properties of the component layers. The proposed approach could be useful for thermally characterizing and guiding the design of novel metal-metal-layered systems involved in diverse technological applications. © Springer Science+Business Media New York 2013.