Dengue virus as a member of mosquito-borne flaviviruses is responsible for an increasing number of human infections worldwide, mainly in tropical and subtropical urban areas. The agent, a single-stranded positive sense RNA virus, is comprised of four serotypes and genetic variation within each serotype can be further divided into different genotypes. Dengue outbreaks were reported in bordering countries during the last years; the latest reported in Paraguay in 2006-2007. In Buenos Aires, 32 dengue cases were confirmed in travelers coming from this country by anti-dengue IgM antibodies detection, RT-PCR and/or isolation in C6/36 cell line. Structural proteins C, prM/M, E and non-structural proteins 1 and 2 from eight viruses were genetically characterized. Phylogenetic inference was performed for the E-protein and all viruses clustered with dengue virus 3 Genotype III. This is the first report of genetic characterization of dengue virus 3 in Argentina.