Wheat yellow mosaic virus (WYMV) isolate HC was used for viral cDNA synthesis and sequencing. The results show that the viral RNAl is 7 629 nucleotides encoding a polyprotein with 2 407 amino acids, from which seven putative proteins may be produced by an autolytic cleavage processing besides the viral coat protein. The RNA2 is 3 639 nucleotides and codes for a polyprotein of 903 amino acids, which may contain two putative non-structural proteins. Although WYMV shares a similarity in genetic organization to wheat spindle streak mosaic virus (WSSMV), the identities in their nucleotide sequences or deduced amino acid sequences are as low as 70 % and 75 % respectively. Based on this result, it is confirmed that WYMV and WSSMV are different species withinBymmirus.