Rhinoviruses are small, non-enveloped, single-stranded RNA viruses with a positive sense genome of ∼7200 bases. The genome contains a single open reading frame (ORF) which is flanked by 5' and 3'untranslated regions (UTR). The ORF encodes a single polyprotein that is post-translationally cleaved into four structural proteins (VP1, VP2, VP3 and VP4) and seven non-structural proteins (2A, 2B, 2C, 3A, 3B, 3C and 3D). Sequences of various sub-genomic regions such as 5'UTR, VP4/VP2, VP1, 3D polymerase and partial 2A have been used to study evolutionary relatedness of HRV-A, -B and -C strains/isolates.