The adhesion of, and corrosion protection provided by, organic surface coatings to underlying metal can be significantly improved if the degreased, etched, and pickled metal surfaces to be coated are first treated with an aqueous solution and/or dispersion of aluminum-zirconium complexes, which are obtainable as the reaction-product of a chelated aluminum component, an organo-functional ligand component, and a zirconium oxyhalide component, with the organo-functional ligand being chemically bonded to the chelated aluminum unit and the zirconium unit in the complex, and are subsequently treated with dilute aqueous solutions, emulsions, and/or dispersions of one or more inorganic and/or organic film-forming materials prior to coating the surfaces with conventional organic surface coatings.