The complete genomic sequence of rose yellow mosaic virus (RoYMV) was determined and found to have all the features that are characteristic of members of the family Potyviridae. The RoYMV genome is 9508 nucleotides long excluding the 3'-poly-(A) tail and contains a single open reading frame encoding a polyprotein of 3067 amino acids. The RoYMV P3 and CI cistrons are shorter than those of other members of the family Potyviridae, and the 6K1 cistron is completely absent. Comparative sequence analysis revealed that RoYMV had highest amino acid sequence identity across the entire genome sequence to brome streak mosaic virus (33 %) and to turnip mosaic virus (30 %) at the coat protein level. Based on its low sequence similarity to known members of the family Potyviridae and phylogenetic analysis, RoYMV appears to be a distinct, previously undescribed, member of this family.