Eight genera and 25 species are recognized among the Nearctic, Mexican, and West Indian Oodini. Four new species are described: Oodinus pseudopiceus (type locality: Hillsborough River St. Pk., Hillsborough Co., Florida); Oodinus similis (type locality: San Quintín, Chiapas, Mexico); Oodinus darlingtoni (type locality: Cauto El Cristo, Oriente, Cuba); and Oodinus edentulus (type locality: 31.8 mi E Francisco Escárcega, Campeche, Mexico). Oodes fluvialis LeConte, 1863, previously recognized as a subspecies of O. americanus Dejean, 1826, is given specific status. The following new synonymies are established: Eulachnocrepis Habu, 1956 with Lachnocrepis LeConte, 1853; Stenocrepis texana (LeConte, 1863), S. chalcas Bates, 1882, and S. chalcochrous Chaudoir, 1883 with S. insulana (Jacquelin du Val, 1857); Stenocrepis quatuordecimstriata (Chaudoir, 1843), S. picipes (LeConte, 1844), S. stenocephala (LaFerté-Sénectère, 1851), and S. sulcata Chevrolat, 1863 with S. mexicana (Chevrolat, 1835). Lectotypes are designated for Oodinus alutaceus (Bates, 1882), Oodes amaroides Dejean, 1831, O. fluvialis LeConte, 1863, O. americanus Dejean, 1826, Stenocrepis texana (LeConte, 1863), S. chalcas Bates, 1882, S. lecontei (Chaudoir, 1857), S. quatuordecimstriata (Chaudoir, 1843), S. picipes (LeConte, 1844), S. cuprea (Chaudoir, 1843), S. tibialis (Chevrolat, 1834), S. femoralis (Chaudoir, 1835), S. elegans (LeConte, 1851), and S. gratiosa (Bates, 1882). The genus-group name Nanodes Habu, 1956, a homonym of Nanodes Schönherr, 1825, is replaced by Nanodiodes, new replacement name. For each genus treated, the following are provided: citation of original description and selected references, notes about synonymy (if required), description, geographical distribution and diversity, and monophyly and phylogenetic relationships. For each species included, the following are given: citation of original description and synonymies, type material, etymology (for new species only), notes about synonymy (if required), diagnosis, description, geographical distribution, bionomics, and phylogenetic relationships (if the genus includes more than two species). Keys to genera and, for each genus, to species are included. The species distributions are mapped, and the important structural features are illustrated.