The study of HBV genome sequence has been an important tool in the understanding of HBV evolution and its genotypes. The mutations in the hepadnaviruses has been of assistance in estimating how the different genotypes branched off from each other. Sequence differences between HBV genotypes can lead to structural differences at the pregenome level and can also lead to remarkable differences at the translational level. These translational differences are also genotype specific. This is a review article.