DNA barcoding provides an operational framework for mammalian taxonomic identification and cryptic species discovery. Focused effort to build a reference library of genetic data has resulted in the assembly of over 35 K mammalian cytochrome c oxidase subunit I sequences and outlined the scope of mammal-related barcoding projects. Based on the above experience, this chapter recounts three typical methodological pathways involved in mammalian barcoding: routine methods aimed at assembling the reference sequence library from high quality samples, express approaches used to attain cheap and fast taxonomic identifications for applied purposes, and forensic techniques employed when dealing with degraded material. Most of the methods described are applicable to a range of vertebrate taxa outside Mammalia.