This study evaluated the antioxidant activities of kimchi at different fermentation times: short-term fermented kimchi (SK; less than 7 days) and over-ripened kimchi (OK; greater than 2 years). In conclusion, antioxidant activity of the OK was significantly higher than the SK. The results of this study suggested that there was an increase in the antioxidant activity of fermented kimchi during the fermentation and ripening processes. (c) 2011, The Society for Biotechnology, Japan. All rights reserved.