Abstract: This study presents a revision of the genus Leptochirus (Coleoptera: Staphylinidae: Osoriinae) considered here part of the Leptochirini tribe. In the same way, is included a revision of two Neotropical subgenera of Leptochirus (Mesochirus and Leptochirus s. str.). The revision of each subgenus is detailed in the two first chapters. Distribution data, new records, redescriptions and descriptions are provided for each taxa. Lectotypes and paralectotypes as well as new synonyms are designated herein. Chapter III includes a cladistic analysis based on external morphology of adults, including internal sexual characters. Terminals that conformed the cladistic analysis included four Leptochirus subgenera (Leptochirus s. str., Mesochirus, Strongyloquirus and Tropiochirus) as well as representatives of the four subgenera of Leptochirini tribe (Plastus, Borolinus, Priochirus and Thoracochirus) and two representatives of two genera of Osoriini tribe (Osorius and Holotrochus). All the terminal taxa came from Neotropical and Oriental regions.