At present eight hepatitis B virus (HBV) genotypes have been characterized: A to H. The most common genotype in Northern Europe is genotype A. So far there is no record of the specific HBV genotype distribution in Iceland. Iceland has a small population whose homogeneity has changed due to increasing migration during the past decades. The distribution of HBV genotypes in Iceland was analyzed using sera from 170 Icelandic patients. The samples were obtained before 1989, during an HBV epidemic among intravenous drug users in 1989 to 1992 and after 1994. A fragment of the HBV S-gene was amplified, sequenced and subjected to phylogenetic analysis. Among samples derived before 1989 genotypes A, C, and D were found. Most of the samples diagnosed during the epidemic belonged to genotype D and a smaller portion to genotype A. This suggests that the epidemic was most likely caused either by an endogenous HBV strain or by a strain imported from Europe or the USA. Among samples obtained after 1994, genotypes A to E and G were found, but the majority were of genotypes A, C, and D. This is consistent with an increase in migration and immigration from regions in Asia and Africa during the past 10 years. Thus, the changing prevalence of HBV genotypes in a small isolated community such as Iceland reflects the influence of migration and increasing contacts with regions outside the Western World.