Thin gold films were vapor deposited onto KCl single crystals under a variety of substrate temperatures, residual gas pressures, and deposition rates. The films were subsequently examined by high‐resolution transmission‐electron microscopy. The use of the defocus contrast technique revealed a large number of small (10–50 Å in size) voids in all of the films investigated. The void density and total void volume were found to be highly sensitive to the substrate temperature and only moderately sensitive to the residual gas pressure during the deposition. Typical values of the void density in films prepared at a residual gas pressure of 10−7 Torr (∠10−5 Pa) ranged from the order of 1010/cm2 at a substrate temperature of 280° C to that of 1011/cm2 at 55° C. Similar results were obtained for a residual gas pressure of 10−4 Torr (∠10−2 Pa).