Tehran University of Medical Sciences Iranian Journal of Public Health 2251-6085 38 1 2009 03 15 41 47 S Milani Research Center, Iranian Blood Transfusion Organization (IBTO), Tehran, Iran Z Sharifi Research Center, Iranian Blood Transfusion Organization (IBTO), Tehran, Iran M Hosseini Dept. of Biology, Faculty of Science, Shahid Beheshti University, Tehran, Iran M Mahmoodian Shooshtari Research Center, Iranian Blood Transfusion Organization (IBTO), Tehran, Iran 2015 10 03 Background: 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. Methods: 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. Results: Genotype D was found the only type in all HBV DNA positive serum samples, in Tehran. Conclusion: Genotype D is dominant among Tehran's blood donors, which is consistent with Iran and the Middle East domi­nant genotype.   https://ijph.tums.ac.ir/index.php/ijph/article/view/3209 https://ijph.tums.ac.ir/index.php/ijph/article/download/3209/3008