Baturite is an important endemic zone of American cutaneous leishmaniasis in the state of Ceara, where an entomologic survey has been carried out to obtain information about transmission of the disease. From October 1989 through August 1991, natural infections with flagellates were detected in 34 of 3,000 Lutzomyia whitmani, five of 1,667 Lu. migonei, three of 5,278 Lu. wellcomei, one of 646 Lu. shannoni, and one of 21 Lu. evandroi. Thirty-five infections were peripylarian (i.e., behind the pylorus in the sand fly gut with a tendency to invade the midgut anterior to the pylorus). Fifteen infections (14 from Lu. whitmani and one from Lu. migonei) have been characterized as Leishmania (Viannia) braziliensis by isoenzyme electrophoresis, incriminating this species as a vector of the parasite in this area. Other possible vectors include Lu. wellcomei, Lu. migonei, and Lu. shannoni. Transmission appears to occur in peridomestic sites, especially around animal enclosures. Most cases of cutaneous leishmaniasis were recorded between September and December in Baturite during the period of study.