The effect of the electron-donor additive o-phenanthroline (Phen) and the electron-acceptor additives 2,3,5,6-tetramethyl-p-benzoquinone (TMQ) and 2,3,5,6-tetrachloro-p-benzoquinone (TCQ) on the antiradical activity of some copper and zinc chelates was studied in the reaction of low-temperature initiated oxidation with air oxygen of polyethylene glycol (PEG-1500) in chlorobenzene solutions. The relative inhibition constants fk(7)/k(6)(1/2) were determined for metal complexes with the M(O, O)(2), M(O, N)(2), M(N, N)(2), and M(S, N)(2) chelate moieties. The introduction of Phen led either to an increase in the inhibiting activity or in the appearance of the catalytic effect. The synergetic inhibition action was found for some chelate-TMQ and chelate-TCQ mixtures. The formation of complexes in the chelate-additive mixtures was shown by voltammetry and spectrophotometry.