A new virus with a dsRNA genome was isolated and characterized from the Suhan-neutari strain (ASI 2504) of Pleurotus ostreatus, which was characterized as long and slightly bent with small caps on the stipe of fruit body. Thirty nm isometric viruses with three dsRNA segments (approximately 2.0, 1.84 and 1.82 kb in sizes) were isolated by ultracentrifugation in sucrose gradients. Western analysis of protein extracted purified viruses with anti-virus polyclonal antibody confirmed that viruses have two specific proteins (36 and 68 kDa). Computer analysis of 2.0 kb segment shows that high sequence identity with RNA-dependent RNA polymerase (RdRp) of partitiviruses, respectively. When compared to other dsRNA mycoviruses in a phylogenetic analysis, OMDV was most related to Pleurotus ostreatus virus 1.