Introduction DNA barcoding is a simple and useful step toward understanding the ecosystem. It also serves to further our interests in biodiversity research [1]. A short standardized sequence (400-800 bp) of DNA can be used to distinguish individuals of a species. This approach was taken, because genetic diversity between species is markedly greater than that within species [2]. Numerous computational analysis methods and systems have been introduced for this purpose [3-5]. The use of this system can provide rapid, accurate, cost-effective, and automatable process for species identification. The success rate of each barcoding application varies significantly among groups. Moreover, global datasets that represent extensive ecosystems are expected to be subjected to particular difficulties, especially in groups in which recent speciation rates are high and effective population sizes are large and reasonably stationary [6]. Several studies of species-level identification have covered many groups of organisms, including birds, fishes, and various arthropods [4, 6-8]. In order to use the barcoding system for species identification, cytochrome c oxidase subunit I (COI) sequences were obtained in this study from 529 sequences, representing 156 species from fish, insects, and shellfish in the Korean peninsula.