Abstract Flavonoids and ascorbic acid are antioxidants usually consumed together in foods, taking this into account, the antiradical capacity of mixtures of ascorbic acid with some representative flavonoids (flavanones, chalcones and flavonols) against the 2,2-diphenyl-1-picrylhydrazyl radical (DPPH ) was evaluated. Antiradical capacities of naringin, naringenin, hesperidin, hesperetin, naringin chalcone, naringin dihydrochalcone, rutin and quercetin were measured alone and in different combinations with ascorbic acid. Experimental and theoretical values of antiradical activities for these mixtures as well as the values obtained in sequential reactions were compared in order to determine synergistic or antagonistic effects. Among the different ascorbic acid–flavonoid combinations analyzed only the mixture with naringin or quercetin exhibited synergistic effects, the mixture activity being 33 and 18% higher than the theoretical value, respectively. On the contrary, antagonistic effects were found in the cases of rutin, hesperidin, naringin chalcone, naringin dihydrochalcone and naringenin. Moreover, only hesperetin showed an additive effect. These behaviours were ascribed to the regeneration of the oxidized species on the basis of the structural features of each flavonoid and their different reactivity against DPPH These results show that the antiradical activity can be modified by the interaction among the mixture constituents and this may be considered to improve antioxidant formulations.