In this study, we analyzed species composition, richness, and monthly and seasonal abundance of sand flies in an urban area, municipality Caxias, state Maranhão, endemic for American visceral and tegumentary leishmaniasis. Sand flies were caught using Center for Disease Control (CDC) light traps in peridomicile (animal shelter) and extradomicile (forest) environments twice a month for 1 yr. A total of 16,332 specimens belonging to 20 species were captured. The predominant species identified in this study were Lutzomyia longipalpis (Diptera: Psychodidae) (Lutz and Neiva 1912) (43.08%) and Lutzomyia whitmani (Diptera: Psychodidae) (Antunes and Coutinho 1939) (43.02%), which occurred throughout the year (every month). The highest abundance of phlebotomine was recorded during the dry season (53.75%) and in the urban peridomicile environment (59.1%), wherein 17 species were found. In the study area, L. longipalpis and L. whitmani are reported to be effective visceral or tegumentary leishmaniasis vectors, respectively, due to their abundance throughout the year.