[Aim]  To increase the speed and accuracy of detection of exotic ants at ports of entry. [Methods]  Mitochondrial COⅠsequences of exotic ants from 3 subfamilies, 16 genera and 18 species were obtained using a first-generation sequencing technique. Two homologous Apis cerana sequences served as outgroups. Sequence variation between species was compared to morphological differences using an ML phylogenetic tree, ABGD analysis, and genetic distance analysis. [Results]  A ML phylogenetic tree classified 18 species of ants on three branches. At the species level, individual ants of the same species were grouped into a single, clearly distinguishable, clade. At the generic level, 16 genera, such as Dolichoderus, Anoplolepis and Camponotus, could also be clearly distinguished. ABGD analysis also clearly distinguished 18 species. The results obtained using molecular methods were consistent with those obtained using morphological classification. Genetic distance analysis indicates that interspecific genetic distances exceeded the intraspecific genetic distances for all 18 species. [Conclusion]  DNA barcoding technology using mitochondrial COⅠgene variation correctly identified 18 exotic ant species described on the basis of morphological differences.