The vitamin C content of cucumber and mung bean sprout was markedly decreased in NaCl-treated tissue by storage at 4°C The ascorbate oxidase (AAO) activity of NaCl-treated vegetables increased according to the NaCl concentration. Increase in AAO activity of NaCl-treated vegetables was a result of the increase to the homogenate when NaCl or other salts were added to the homogenizing buffer. These results suggest that the increase in the amount of free AAO resulted in the decreased AsA content of NaCl-treated tissues.