We augmented existing genetic datasets with nucleotide sequences from Recombination Activase Gene 1 (RAG-1) and an intron in the RNA fingerprint protein 35 (R35) for Macrochelys temminckii (Chelydridae), and from the nuclear gene Glyceraldehyde-3-phosphate Dehydrogenase (GAPDH) for Macrochelys temminckii, Apalone spinifera (Trionychidae), Trachemys scripta (Emydidae), Sternotherus odoratus (Kinosternidae), Staurotypus triporcatus (Kinosternidae), Chelydra serpentina (Chelydridae), Dermochelys coriacea (Dermochelyidae), Platysternon megacephalum (Platysternidae), and Chelonia mydas (Cheloniidae) to address the phylogenetic relationships of the Chelydridae. Our study finds support for a sister group relationship between Chelydridae and either the clades Kinosternoidea (Kinosternidae Dermatemydidae) or Chelonioidea (Cheloniidae Dermochelyidae). Further analysis also suggests that the speciation events leading to these clades occurred in rapid succession, within approximately one million years of each other.