Sand flies are insects of medical and veterinary importance, because some species are able to transmit several pathogens such as Bartonella spp., Phlebovirus spp., and protozoan parasites of the genus Leishmania (Ross). They are widely distributed in the Americas, with recordings ranging from Canada to Argentina. Approximately 500 Phlebotominae species are known in the Americas, of which it is considered that at least 56 are involved in the transmission of leishmaniasis (Maroli et al. 2012). Previous studies have shown that the phlebotomine fauna in Argentina consists of 32 species distributed in 14 provinces (Quintana et al. 2012; Sábio et al. 2015; Salomón et al. 2010). Of these species, Lutzomyia longipalpis (Lutz & Neiva), Nyssomyia neivai (Pinto), Ny. whitmani (Antunes & Countinho), Cortelezzii complex [Evandromyia cortelezzii (Brèthes) - Ev. sallesi (Galvão & Coutinho)], Micropygomyia quinquefer (Dyar) and Migonemyia migonei (França) have been found with DNA of Leishmania spp. (Moya et al. 2015). Five new records of species in the province of Chaco, obtained from different projects carried out between 2001 and 2015, four of which are also new records for Argentina, are described in this article. Their importance as potential vectors and the correct determination of the sympatric species is also discussed.