The New World species of Oedichirus Erichson, 1839, are revised, redescribed, or newly described, illustrated, and included in keys for identification. The morphology of the ventral pterothoracic sclerites is examined and Matsuda's (1970) interpretation is largely adopted over that of Ferris (1940b). Newly discovered characters of the median gonocoxal plate and associated vulvar plate, including its microstructures, are discussed. Prior to the present paper New World species were known in Brazil and Costa Rica, but are herein newly reported for the Dominican Republic, Mexico, Ecuador, Peru, Bolivia, and Argentina; a specimen intercepted at a port in the United States was said to have come from Nicaragua. Eight species were previously described; 19 new ones are added herein, 12 from Brazil (O. apiculus, O. batillus, O. bicristatus, O. bullaglaber, O. bullahirtus, O. clavolateralis, O. clavulus, O. echinatus, O. exilis, O. glabrihamus, O. lunatus, and O. procerus), two from Mexico (O. isthmus and O. sinuosus), and one each from Argentina (O. misionesiensis), Bolivia (O. dilophus), Ecuador (O. distortus), Peru (O. hamatus), and Dominican Republic (O. dominicanensis). A neotype is designated for O. geniculatus and lectotypes are designated for O. brunneus Wendeler, O. pictipes Bierig, O. ohausi Wendeler, O. optatus Sharp, O. sparsipennis Bernhauer, and O. speculifrons Bernhauer. Some species are included in species groups.