Background: Hantavirus lives and reproduces in the body of rodents. Rattus norvegicuswas one found in the Kepulauan Seribu islands of Indonesia. Hantavirus species Seoul virus (SEOV) is a negative single chain RNA viruses included in the family Bunyaviridae. It has a few specific genes, especially genes S that can be developed for a diagnostic test. The aim of this study was to ascertain the character of gene S of hantavirus species Seoul virus. Methods: Gene sequencing of S Seoul virus from lung tissue of rodents was conducted. DNA fragment sequencing used primer pairs of SEOS-28F and SEOS -360R, VNS-1501F and VNS-CSR. The results of sequencing were analyze by seqscapeprogram to obtain a sequence of nucleotides, and analyzed by Mega5 programs. Phylogenetic analysis was done for homology nucleotides and amino acids which were compared to other hanta virus species from the gene bank. Results: The comparison analysis showed, the highest homology from strain KS74 was 88.4% and the lowest from strain KS90 was 87.2%. The highest homology of amino acids sequence compared with Seoul virus came from strain KS74 was 91.3% and the lowest came from strain KS90 was 89.5%. Conclusion: Gene S of viruses was found in Kepulauan Seribu in Indonesia and it was comparable to that found in Singapore and Korea. (Health Science Indones 2014;1:1- 6).