The Indochinese box turtle Cuora galbinifrons is a polytypic, critically endangered species from Vietnam, Laos, and Hainan Island, China. We analyze up to 1790 bp of mitochondrial DNA under maximum parsimony and maximum likelihood criteria to test if the five historically recognized subspecies represent evolutionary lineages, and to elucidate the relationship of C galbinifrons to other Cuora. C galbinifrons is composed of three major mitochondrial DNA clades corresponding to the three subspecies galbinifrons, bourreti, and picturata. These three lineages are also morphologically diagnosable, and consequently we recommend elevating each to full species. Cuora galbinifrons hainanensis nests within the galbinifrons clade, and we retain it as a synonym of galbinifrons, as supported by morphology. Cuora “serrata” is known to be a hybrid of male Cuora mouhotii and female C galbinifrons, and our findings show that C “serrata” originates from both female galbinifrons and bourreti. Little or no mitochondrial DNA variation was found among the morphologically distinct species Cuora aurocapitata, Cuora pani, and Cuora trifasciata, for which hypotheses are proposed. Recognizing galbinifrons, bourreti, and picturata as separate species has consequences for ongoing ex situ captive breeding programs and prioritization of in situ conservation activities, particularly in Vietnam. (C) 2003 Elsevier Inc. All rights reserved.