The present invention provides for the use of certain oil soluble iodides to enhance the oxidation resistance of lubricating oils and fuels, and for the novel formulated compositions containing these iodides. Oil soluble iodides such as C.sub.16 to C.sub.78 alkyl ammonium as well as oil solubilizable or dispersible iodides such as CoI.sub.2, CuI, KI and NaI in combination with a suitable dispersing agent may be used. Typically a minor amount of additive, from about 40 to about 1000 ppm is used. The additive is effective as an antioxidant in a variety of different types of base and formulated oils.
