This study was carried out to investigate the physicochemical characteristics and antioxidant properties of mulberry juice (MJ) and mulberry vinegar (MV). MV, with acidity of 6.05% and a pH 3.06, was obtained from MJ after 8 days with alcohol fermentation and 20 days with acetic acid fermentation at 30℃. After fermentation, the major sugars in MV were lactose, glucose, and fructose, showing 1,310.06, 293.20, and 41.25 mg%, respectively. The major organic acids in MV were acetic acid (2,725.59 mg%), citric acid (524.66 mg%), and succinic acid (480.63 mg%). The total free amino acid content of MV, such as lysine, arginine, phenylalanine, and tyrosine, was 34.52 mg%. MJ and MV showed radical scavenging activities with respect to 1,1-diphenyl-2-picrylhydrazyl (DPPH), hydroxyl (OH), superoxide anion (O 2-), and nitric oxide (NO) radicals in dose-dependent manner, which were closely related to the total polyphenol and flavonoid contents in MJ and MV. In addition, a strong scavenging effect with regards to the OH radical was observed in MJ and MV, an IC 50 value of 0.04 μg/mL. In particular, MV showed a higher O 2 radical scavenging activity than that of MJ. These results suggest that MV can be used as a functional vinegar with antioxidant activity against free radicals.