This study was performed to investigate the antagonistic properties of mushroom strains against Korean oak wilt pathogen (Raffaelea quercus-mongolicae) by assessing their predominance on potato dextrose agar plates after pairing culture. Among the total of 158 strains of mushroom tested, thirty-three strains showed no antagonistic activities against the pathogen in both the short term (6~7 days) and long term (27~31 days). Ninety-six strains of tested mushrooms had a weak or no long term antagonistic activity. The antagonistic activities of 29 strains were higher than those of other strains with the levels of $geq$ R+ and $geq$ R for short and long term, respectively. We found that these strains with antagonistic activities against R. quercus-mongolicae belong to the species of mushrooms living on different host plants such as conifers, oaks and other broad-leaved trees. In order to use the trees damaged by Korean oak wilt as a resource(bed-log) for cultivating mushrooms, seven strains of antagonist 29 strains were selected as follows; Laetiporus sulphureus KFRI 654, Laetiporus miniatus KFRI 914, Lentinula edodes KFRI 269 and 764, Pycnoporus coccineus KFRI 588, Schizophyllum commune KFRI 832 and Trametes versicolor KFRI 100.