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We have shown that ascorbic acid in neutral aqueous media rather rapidly interacts with nitrite ions to form dehydroascorbic acid. If the acidity of solution is sufficiently high (pH value does not exceed much above ∼7) and the nitrite concentration is of order of 0.05 M or more, the only mechanism of the reaction under aerobic conditions includes, as the first, rate-limiting reaction step, the nitrosation of ascorbic acid. A second-order reaction kinetics was observed in respect to protons, which determined a sharp acceleration of the ascorbic acid conversion when the acidity of the medium was raised. Hence, a suggestion can be drawn that the presence of nitrites in vegetables under acidic storage strongly increases the decay of vitamin C. Keywords: Ascorbic acid; nitrite; oxidation; nitrosation

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