The present invention provides methods, kits, and oligonucleotides for detecting and analyzing the nucleotide sequence of a reverse transcriptase (RT) region of the polymerase (Pol) gene of Hepatitis B Virus (HBV). In certain embodiments, a target RT region is amplified and subjected to DNA sequencing. The sequence obtained is compared to one or more DNA sequences characteristic of an HBV genotype or serotype, and/or one or more DNA sequences characteristic of an HBV mutation that confers resistance to a drug or vaccine, to determine the HBV genotype or serotype of the amplified product and/or the presence or absence of one or more DNA sequences characteristic of an HBV mutation that confers resistance to a drug or vaccine.