The oxidation of 1,3-dimethyladamantane by hydrogen peroxide in the presence of "lacuna" polyoxometallates (POM) of the general formula RMX(H2O)W11O39 (M = Fe, Co, Cu, Mn; X = Si, P; R -hexadecylpyridinium) has been established. With polyoxometallates containing Si, Mn and Si, Fe, oxidation proceeds only by the tertiary carbon atom. To produce oxidation products by the secondary carbon atom, a POM containing P and Fe is most promising.