Eight edible mushrooms grown in Korea were extracted with ethanol at room temperature for 24 hr. The extracts were investigated for their antioxidant activities as measured by 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity and 2,2-azino-bis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radical cation scavenging activities. Among the mushroom extracts evaluated in this study, the ethanolic extracts from Ganoderma lucidum and Pleurotus eryngii showed the greatest potential antioxidant activity, by producing 85 and 88% inhibition in DPPH radical scavenging method and 219 and 165 mg ascorbic acid equivalent antioxidant capacity (AEAC), respectively. Total phenolics and total flavonoids in the ethanolic extracts were determined by spectrophotometric method. Positive correlations were found between total phenolic contents in the extracts and their antioxidant activities, suggesting that phenolic contents in the mushrooms extracts are mainly responsible for their antioxidant activities.