Abstract: Nucleic acid sequence comparison between the Egyptian strain (GI 19) and the American strain (ND 18) of barley stripe mosaic virus (BSMV) revealed a high degree of sequence similarity of γ RNAs, comparing to βRNAs of both strains. On the other hand nucleotide and amino acid sequences of the two strains revealed differences in the 5` untranslated region (UTR) between the coat protein and Bb gene. It was clear that, five bases, and 18 out of 116 amino acids were found different, three amino acids insertion, and one amino acid deletion. Little differences were also observed regarding the 5` UTR of RNA γa, as six nucleotides were changed, 12 out 162 amino acids were differed and one amino acid deletion. G1 19 strain was cross reacted specifically with the monoclonal antiserum raised against the coat protein of ND 18 stain and the two coat proteins were indistinguishable in their sizes.