The sequence variability of Barley yellow dwarf virus-PAV (PAV) and Barley yellow dwarf virus-MAV (MAV) was studied by comparing 502 nucleotides from the coat protein-encoding region of six isolates from Latvia and four from Sweden. The diversity within MAV was low (>97% sequence identity), also when compared to isolates from USA and China. In contrast, the variability among PAV isolates was greater and phylogenetic analysis including isolates of a wide geographic origin detected two major clusters, of which both contained isolates from Latvia and Sweden. A new distinct variant of BYDV-PAV was discovered in Latvia, and because of the sequence difference it is proposed to belong to a new species (BYDV-OYV).