Gas turbine engines are considered to be among the most hostile operating environments for conventional material systems.  Increasing demands for higher engine performance, thermal efficiency and durability of components have led to the development of thermal barrier coating systems.  Currently, the use of these coatings is limited because of premature failure of the ceramic top coat, which occurs due to the oxidation behaviour of the underlying metallic bond coat (formation of thermally grown oxide - TGO).  The purpose of this study is to investigate and compare the oxidation behaviour of conventional and nanocrystalline CoNiCrAlY bond coats. The nanocrystalline feedstock powder is produced from the conventional feedstock powder using the cryogenic milling process. Conventional and nanocrystalline bond coats are produced using the Cold Spray process, thus ensuring conservation of the original feedstock chemical composition and structure in the coating.  The oxidation behaviour is determined by means of isothermal oxidation experiments consisting of heat treatments in air at 1000°C for various periods of time.  The effect of the dispersoïds formed during cryogenic milling and present in the nanocrystalline coatings is examined. The feedstock powders and the resulting coatings are characterized using Scanning Electron Microscopy (SEM), X-Ray Diffraction (XRD) and Transmission Electron Microscopy (TEM).