This study examined the genetic diversity of the Reeves’ turtle populations collected in three different locations (GangjinYeongam, Geumgok and Gurye) of the southwestern region of South Korea based on the mitochondrial cytochrome B (cytB) gene polymorphisms. From 128 cytB sequences newly obtained in this study, six cytB haplotypes were detected. Among three populations, the Gurye population (n=14) had five haplotypes with high levels of haplotype diversity (Hd) (0.824±0.070) and nucleotide diversity (π) (0.00457±0.00051). The Gangjin-Yeongam population had (n=22) had two haplotypes with relatively higher level of Hd (0.515±0.081) and relatively low level of π (0.00207±0.00029). Interestingly, the largest Geumgok population (n=92) had just two haplotypes with low levels of Hd (0.390±0.044) and π (0.00171±0.00019). Neutrality test results showing high positive values estimated that the Geumgok and Gangjin-Yeongam populations had recently gone through a genetic bottleneck. The results of phylogenetic analysis showed a pattern of geographical genetic differentiation of cytB haplotypes in South Korea and China, indicating that several haplotypes found in the South Korea but branching together with those in the Chinese origins were recently introduced from China at the end of the 20th...