The requirements for increasing operating temperatures in gas turbines and fuel fired energy systems is linked to the use of protective coatings able to improve oxidation and corrosion resistance of structural materials. MCrA1Y-type overlay coatings have been especially designed to protect airfoils and other hot gas component superalloys against hot corrosion induced by molten salts in lower grade fuel and aggressive environments. However, aluminide coatings modified by additional elements have gained renewed interest because they offer an economical alternative to physical vapor deposition or plasma spray coating processes used to apply the MCrA1Y’s. Of the possible modifiers, chromium and platinum are the most prevalent elements used. Although they have been in field service for a number of years, there are some controversies on the reasons for their beneficial effects. The present literature on the corrosion behavior of chromium and platinum modified coatings is reviewed and updated in light of the structural dependence of corrosion resistance for both coating types. The formation mechanisms and the related structures of chromium aluminides are presented together with results of recent investigations aimed at defining the structural variations of platinum aluminide coatings which depend on the deposition parameters, that is, the platinum prealuminizing treatment and the subsequent aluminizing process.