Virion RNA of Kunjin virus was translated in rabbit reticulocyte lysates at a rate (7000 daltons/min) approaching that observed previously in vivo. As many as 18 polypeptides were translated and shown by tryptic peptide mapping to be closely related to one another and to contain some of the elements of envelope (E) and most of the elements of core (C) proteins of Kunjin virus. None of the products resolved in gels were precipitated by antiserum to purified E protein, but the larger products were precipitated by an antiserum against all the Kunjin virus-specified proteins. No evidence was obtained of translation of the non-structural proteins, despite attempts to retain or perturb the structure of the virion RNA. As many as 50% of the amino acid sequences in the peptide maps were not identifiable.