A novel double-stranded RNA (dsRNA) mycovirus, designated Fusarium oxysporum f. sp. dianthi mycovirus 1 (FodV1), was isolated from a strain of the phytopathogenic fungus F. oxysporum f. sp. dianthi. The FodV1 genome had four dsRNA segments, designated, from the largest to the smallest one, dsRNA 1, 2 3, and 4. Each one of these segments contained a single open reading frame (ORF). dsRNA 1 (3555 bp) and dsRNA 3 (2794 bp) encoded a putative RNA-dependent RNA polymerase (RdRp) and a putative coat protein (CP), respectively. dsRNA 2 (2809 bp) and dsRNA 4 (2646 bp) contained ORFs encoding hypothetical proteins (named P2 and P4, respectively) with unknown functions. Analysis of its genomic structure, homology searches of the deduced amino acid sequences, and phylogenetic analysis all indicated that FodV1 is a new member of the family Chrysoviridae. This is the first report of the complete genomic characterization of a mycovirus identified in the plant pathogen Fusarium oxysporum.