Tremella fuciformis were collected from dead Quercus limbs at Haenam, Jeonnam province in 2003 and cultured in artificial media with Hypoxylon sp., a symbiotic fungi. Various extracts were prepared from this cultured mushroom according to three experimental settings and their antioxidant properties were examined. Antioxidant activity of extracts from Tremella fuciformis was evaluated by scavenging activity of 2,2´-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) radical cation (ABTS+), 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity and superoxide dismutase(SOD)-like activity. Among the extracts, the chloroform extract from in experimental setting I showed the most potent radical scavenging activity in each assay, showing 56% of DPPH radical scavenging activity at 1,000 ppm and 35.7% of ABTS+scavenging activity at 1,000 ppm. Total phenolic content were estimated in various extract by using caffeic acid, chlorogenic acid, catechin, and ferulic acid as standards. Correlations of phenolic content in each extracts with antioxidant activity will be discussed in this study.