The initial growth of Cu on (111) Ag surfaces was examined in situ by RHEED and later by TEM and TED. The substrates were very smooth (111) Ag films, single positioning oriented, evaporated on NaCl/mica in UHV just prior to Cu growth. The Cu overgrowths were double positioning oriented and contained microtwins. The mode of Cu growth depended on the substrate temperature. Cu deposited at 210 °C formed island-type overgrowths. At 25 °C, Cu formed a very smooth overgrowth up to about two monolayers. Thereafter island growth occured. From the smooth Cu–Ag bilayers, anomalous RHEED patterns were obtained similar to those observed by Gradmann and Krause on Ag–Cu bilayers. These authors interpreted their diffraction patterns in terms of a postulated regular network of interfacial dislocations. However, high-resolution TEM of Cu–Ag bilayers in the present work revealed a very low density of dislocations and only an extremely rare irregular network.