Visceral and cutaneous leishmaniasis are major endemic diseases in northeast Brazil. The objective of the current study was to determine the species and geographic distribution of potential sand fly vectors of Leishmania in the state of Rio Grande do Norte. Sand flies were captured using CDC light traps in 30 municipalities distributed throughout the 8 geographic zones of the state. Twelve Lutzomyia species were identified. Lutzomyia longipalpis Lutz & Neiva was the most prevalent and accounted for 85.59% of the sand fly captured. The remaining species were distributed as follows: L. evandroi Costa Lima & Antunes (10.83%), L. oswaldoi Mangabeira (0.99%), L. sallesi Galvão & Coutinho (0.58%), L. intermedia Lutz & Neiva (0.53%), L. lenti Mangabeira (0.53%), L. migonei França (0.49%), L. walkeri Newstead (0.24%), L. goiana Martins, Falcão & Silva (0.15%), L. samueli Deane (0.04%), and L. capixaba Dias, Falcão, Silva & Martins (0.03%), and L. peresi Mangabeira (0.01%). L. longipalpis, which is known to be a vector of Leishmania chagasi Cunha & Chagas (L. donovani chagasi), was captured in 93% of municipalities distributed across all geographical areas of the state and its distribution was independent of obvious climatic and topographic parameters. It was identified in all municipalities where human visceral leishmaniasis had been reported. In contrast, climate and topography appeared to be important for other Lutzomyia species. For example, L. intermedia and L. migonei, which are known to transmit Leishmania braziliensis Viana, were geographically restricted. They were captured in municipalities where cases of cutaneous and mucosal leishmaniasis had been reported. The widespread distribution of L. longipalpis, its adaptation to peridomicillary settings, and its ability to transmit L. (d.) chagasi suggest that a large number of persons may be at risk of acquiring visceral leishmaniasis in the state of Rio Grande do Norte, Brazil.