In this work, we study the impact of the phonon thermal conductivity of Silver (Ag) and Gold (Au) on the interface resistance of metal-nonmetal contacts at room temperature. The thermal conductivity of both metals is determined for bulk and thin films of varying thickness using non-equilibrium molecular dynamics (NEMD) simulations. Likewise, we determine the thermal interface resistance due to phonons of metal films embedded in a nonmetal layer composed of Silicon (Si). Based on a two-temperature model (TTM) for electrons and phonons, we determine the thermal resistance due to electron-phonon interactions and the variation of the film resistance of Ag and Au layers as a function of their thickness. The latter considering the estimated phonon contribution to the thermal conductivity of the studied metals obtained with our NEMD simulations. Two important results are presented in this work. First, we have found for the studied metals that at room temperature phonons contribute less than 1.0 % to the bulk thermal conductivity; and that their relative contribution to the conductivity and its variation with the film thickness significantly impacts the overall film resistance of metallic films. © 2011 IEEE.