Faced by a growing need of identification and delimitation of new and established cryptic species that are being lost at an increasing rate, taxonomists can now more than ever take advantage of an enormous variety of new molecular and computational tools. At this moment they should be open to all new available technologies in the so called 'technology-driven revolution' in systematics. The use of the 'DNA barcode' has been discussed by those applying successfully this approach to identify and diagnose species and by those who believe that the flaws in the use of this molecular marker are as many as to negate the worth of its employment. For insects of the order Lepidoptera neither side seems totally correct or wrong, and although many groups of lepidopterans have been taxonomically resolved by using exclusively or additionally this marker for diagnoses, for others the 'barcode' helped little to resolve taxonomic issues. Here we briefly present some pros and cons of using DNA barcode as a tool in taxonomic studies, with special attention to studies with groups of Lepidoptera developed in the last few years.