AbstractThe species of the genus Sepedophilus (Staphylinidae: Tachyporinae) of America north of Mexico are revised. Thirty species are recognized. Thirteen new species are described: wickhami from the northeastern United States and southeastern Canada; brachypterus, frosti, micans, ctenidialis, and kiteleyi from eastern North America; beckeri from the southcentral United States; and hermani, smetanai, stephani, arizonensis, coronadensis, and velox from the southwestern United States. The following species names are placed in synonymy: knoxii LeConte and carissimus Hatch (= littoreus Linnaeus); imbricatus Casey, limuloides Casey, and elongatus Blatchley (= testaceus Fabricius); corticola Casey (= cinctulus Erichson); virginiae Casey (= velocipes Casey); and subtilis Casey (= debilis Casey). The species cinctulus Erichson and bisignatus Horn, formerly considered as synonyms of opicus Say and bipustulatus Fabricius respectively are recognized as valid species. The Palearctic species marshami Stephens is reported for the first time from the Nearctic region. The usage of the generic group names Sepedophilus Gistel, Conurus Stephens, Conosoma Kraatz, and Conosomus Motschulsky is discussed. The North American species are divided into 12 species groups based on an examination of the Nearctic, Neotropical, and Palearctic faunas. The distribution of each species is mapped, and the male and female eighth abdominal sternites and tergites, the male genitalia and other diagnostic characters, are illustrated. A neotype is designated for Tachyporus opicus Say, and lectotypes are designated when necessary for all the North American species of Sepedophilus described by Gravenhorst, Erichson, LeConte, Horn, and Casey. A diagnostic key for all the species except S. heathi Wasmann is given. A brief discussion of the nomenclatural history of the genus, of collecting techniques, and of the major diagnostic characters is included.