Oxidation and hot corrosion in sulphate, chloride and vanadate environment of a cast nickel base superalloy are discussed. Weight gain studies are carried out in air for the uncoated and coated samples. The corrosion products are analysed and the possible mechanisms of corrosion based on the corrosion compounds are discussed. The variation of weight gain with time indicated a parabolic growth of oxides. The outer layers consisted of oxides and in case of hot corrosion, in addition to oxide outer layer, internal sulphidation was also noticed.