Lead selenide nanocrystalline films of a controlled thickness have been obtained using vacuum deposition onto substrates of C-29 glass, part of which were oxidized in a dry air atmosphere. The surfaces and cleavages of both initial and oxidized PbSe films are studied using scanning electron microscopy. The qualitative and quantitative estimation of the elemental content in the subsurface region of all studied films based on PbSe is investigated using X-ray microanalysis. The presence of lead selenide and lead selenite on the surface of the films under study is proven, and the principle possibility of forming PbSeO3 films from PbSe films is shown.