A novel double-stranded RNA (dsRNA) mycovirus, designated Bipolaris maydis partitivirus 1 (BmPV1), was isolated from the plant pathogenic fungus Bipolaris maydis. The BmPV1 genome has two dsRNA segments. The larger segment (1,930 bp) has a single open reading frame (ORF) with a conserved RNA-dependent RNA polymerase domain. The smaller segment (1,790 bp) contains a single ORF encoding a putative coat protein. Homology searches and phylogenetic analysis indicated that BmPV1 is representative of a new species within the genus Alphapartitivirus.