1. A study has been made of the antioxidant effectiveness of [binary] mixtures of three phenolic inhibitors-2,6-di-tert-butyl-4-methylphenol, 4,4′-methylene-bis(2,6-di-tert-butylphenol), and 2,2′-methylene-bis(4-methyl-6-tert-butylphenol)- and of mixtures of these phenolic inhibitors with p-hydroxydiphenylamine and diphenylamine. 2. The action of inhibitors in a mixture is determined both by the structure of the compounds and by their ratio in the mixture. 3. Synergistic effects were shown by all mixtures of a phenol with diphenylamine, the mixture of MB-1 with Ionol, the mixture of 22–46 with p-hydroxydiphenylamine, and also the mixture of p-hydroxydiphenylamine with 22–46 when the p-hydroxydiphenylamine content was above 35 mole %.