ABSTRACT
Hepatitis B virus [HBV] is one of the major causative agents of acute and chronic liver disease worldwide and is believed to be responsible for a million deaths annually. On the basis of a comparison of complete genomic sequences, HBV has been classified into eight genotypes A-H which show a geographical distribution. Some genotypes are associated with different clinical outcomes. Identification of HBV genotypes is important to begin and follow up the treatment. In this cross-sectional study, the serum samples of blood donors were collected from Tehran Blood Transfusion Centers in period during "2005-2006". Sera of 55 blood donors who were positive for hepatitis B surface antigen were selected. DNA was extracted using commercial kit and the S gene sequence was amplified by nested-PCR. PCR products were then analyzed for restriction enzymes that would be genotype specific. Genotype D was found the only type in all HBV DNA positive serum samples, in Tehran. Genotype D is dominant among Tehran's blood donors, which is consistent with Iran and the Middle East dominant genotype