The oxygen plasma etching resistance of plasma polymerized organometalic film was measured. The films were deposited by downstream plasma deposition using gaseous mixtures of an organic monomer (C3H6) and a metal‐containing monomer tetramethyltin or tetramethylsilane. By changing the flow‐rate ratio of both monomers, the metal content of the film was reproducibly varied from 0% to 27%. It was found that the O2reactive ion etching rate depended on metal content in polymer, discharge power density, and oxygen gas pressure. High oxygen plasma etching resistance was obtained for films which contained even a few percent of metal. From the results of electron spectroscopy for chemical analysis and Auger electron spectroscopy measurements, it was observed that the metal‐oxidized layer was formed on the surface during oxygen plasma etching.