Abstract <p>Over 20 years of extensive studies on DNA barcoding of various types of multicellular organisms have resulted in the selection of specific markers for multiple taxonomic groups, development of primers for many selected markers, establishment of DNA barcodes for more than 400 thousand species, and creation of the BOLD database. Next-generation sequencing methods allow DNA barcodes to be obtained immediately for many samples, including those stored in museum collections. DNA barcode analysis has revealed many previously unknown and undescribed species in various animal groups. DNA barcoding has been successfully used in many practical applications. However, certain problems and controversial issues remain, primarily, regarding description of new species based on DNA barcodes and the accuracy of sample identification using reference libraries.</p>