[en] γ-radiolysis of aqueous solutions of binary redox mixtures of NO₂^- and IO₄^- ions was studied as a function of the reactant concentrations and the absorbed dose. Solutions of sodium nitrite and potassium periodate in distilled water were irradiated by γ-ray from 74 TBq source of Co-60. A comparison of the G(NO₃^-) and G(IO₃^-) in the mixture with those in the pure systems showed that the yield of the former is higher while that of the latter is lower in the mixture. A mechanism, based on the reactions of the primary radiolytic products of water with the solute ions, has been proposed to explain the observed yield. A study of the competitive kinetics has yielded a value of 0.35 for the ratios of the rate constants of the hydrated electron with NO₂^- and IO₄^- ions. (T.I.)