DNA barcoding is a system designed to provide species identification by using standardized gene regions as internal species tag. Foreseen since its earlier development as a solution to speed up the pace of species discovery, DNA barcoding has established as a mature field of biodiversity sciences filing the conceptual gap between traditional taxonomy and different fields of molecular systematics. Initially proposed as a tool for species identification, DNA barcoding has also been applied in taxonomy routines for automated species delineation. Species identification and species delineation, however, should be considered as distinct activities relying on different theoretical and methodological backgrounds. The aim of the present review is to provide an overview of the use of DNA sequences in taxonomy, since the earliest development of molecular taxonomy until the development of DNA barcoding. We further present the differences between procedures of species identification and species delineation and highlight how DNA barcoding proposed a new paradigm that helps promote more sustainable practices in taxonomy