This study was carried out to examine the antioxidant effects of cheonggukjang combined with Phellinus linteus extract. The electron-donating activity (EDA) of cheonggukjang containing 0.3% P. linteus extract (0.3% CPLE) was higher than that of cheonggukjang only. EDA of the ethanol extract from cheonggukjang was higher than that of the water extract. The water and the ethanol extracts showed strong antioxidant activity with regard to peroxide value. However, the ethanol extract showed a higher peroxide value than the water extract. The nitrite scavenging activity of the ethanol extract was greater than that of the water extract, crresponding to the EDA and peroxide values for each extract. Therefore, the antioxidant effects were enhanced by adding 0.3% of extract from P. linteus in manufacturing cheonggukjang. It is suggested that P. linteus extract could be put into practice as an effective antioxidant agent.