To distinct the commercial strains in Pleurotus spp., 81 strains in eight Pleurotus species were used. DNA fingerprinting using URP-PCR was conducted to determine the phylogenetic relationships among Pleurotus strains. DNA profiles of Pleurotus species obtained by twelve URP primers were analyzed for genetic similarity by NTSYS program. We could divide strains into ten clusters, in which three of them belong to P. ostreatus and the others to the different species, respectively. At the 76% similarity level, 70 P. ostreatus strains were distinguished into three clusters. Cluster I contained 35 strains and some of them showed almost 100% similarity, one strain closely related to Weonhyeong and six strains closely related to Wangheukpyeong. In cluster II, twenty-one out of 23 strains showed 100% to Suhan. Cluster III contained twelve strains, including six strains closely related to Chunchu-2. The results suggested that there are many same strains with different names in mushroom spawn market.