A new subspecies of Chelodina mccordi is described from Timor-Leste (East Timor). The nominate subspecies Chelodina m. mccordi is endemic to the small island of Roti to the southwest of Timor. The new subspecies has a very limited distribution in the area of Lake Iralalaro in Lautém District near the eastern tip of Timor-Leste and is endemic to that nation. In some morphological characters, the new subspecies is intermediate between C. m. mccordi from Roti and Chelodina novaeguineae from the island of New Guinea, but, in supporting its subspecific taxonomic status, the new taxon shows more similarities to the nominate form than to C. novaeguineae. The nominate form C. m. mccordi on Roti Island was nearly extirpated by commercial trade in the recent past and has been listed as critically endangered in the IUCN Red List since 2000. Chelodina mccordi is the only species of the genus listed in CITES Appendix II. As a subspecies of C. mccordi, the new taxon from Timor-Leste is automatically included in CITES Appendix II, meaning that any international export of this new taxon to a CITES signatory country requires an export permit from the government of Timor-Leste. This legal requirement will hopefully spare the new subspecies from Timor-Leste the fate of the nominate subspecies from Roti Island, to be nearly driven onto the cusp of extinction through commercial trade shortly after its description as a new taxon.