InSb is a compound semiconductor which is used in many device applications. The use of native oxides as a dielectric layer in semiconductor devices has the advantages of being relatively free from contamination and the ease of growth as compared to the deposition of dielectric layers by other methods. Two methods of oxidation of InSb surfaces were tried, thermal and anodic oxidation. It was found that the thermal oxides were conducting in nature and have low electrical resistivity. On the other hand, anodic oxides exhibited good dielectric properties with resistivity varying in the range 10(8) to 10(10) Omega cm. To explain this behaviour X-ray photoelectron spectroscopy studies were performed on the surface as well as in the bulk of the oxides. It was found that the thermal oxides contain free antimony which was absent in anodically grown oxides. The results were analysed and the kinetics of oxidation are discussed. The use of anodic oxidation for diffusion depth profiling is also illustrated.