The effects of some sodium salts, namely Na2SO4, NaCl, NaNO3 and Na2CO3 coatings, on the high-temperature oxidation behaviour of Nimonic-80A (N-80A) alloy at 1173 K in a slow current of air are presented. The oxidation kinetics and effects of salt deposition on the N80A alloy were investigated. The alloy is more severely attacked by NaCl than by Na2SO4, due to the formation of volatile chlorides. NaNO3- and Na2CO3-induced alloy seem to be more aggressive than Na2SO4 and NaCl due to the evolution of nitrogeneous and CO/CO2 gases respectively. The scale morphologies were determined on the basis of X-ray diffraction analysis and scanning electron microscopic techniques.