Plasma deposition techniques have been examined for production of air-stable films consisting principally of beryllium and carbon. By plasma polymerization of diethylberyllium, films have been made with Be content above 50%, O content near 1%, excellent composition uniformity and reasonable surface smoothness. It appears necessary, for oxygen stability, to deposit these films at T>250°C; at that temperature, the Be is incorporated, at least in part, as a carbide; the measured film densities—2.1–2.5 g/cm3, are near that of Be2C. Permeability to H2 is sufficent to allow microballon filling at 105°C without subsequent loss of H2 at room temperature. Combined sputtering of Be and deposition of a methane plasma polymer has been found similarly effective in forming beryllium/carbon films with Be content above 50 at. % and O content near 1%. These films have not been as extensively studied.