Abstract. In December 2013, chikungunya virus (CHIKV) was isolated for the first time in the Western Hemisphere (WH) during an epidemic on the island of St. Martin. Subsequently, the virus has spread to 42 countries or territories in the Caribbean, Central, South, and North America. In this study, we have determined the full genomic sequences of 29 temporally and geographically diverse CHIKV strains from 16 countries of the WH. Phylogenetic analyses revealed minimal evolution among compared emergent CHIKV strains of the New World.Chikungunya virus (CHIKV) is a single-stranded RNA virus (family Togaviridae, genus Alphavirus) that is transmitted by Aedes species mosquitoes. The virus was first isolated in Tanzania in 1953; however, descriptions of probable CHIKV epidemics occurring in the nineteenth century are found in the literature.