A study of the natural infection of phlebotomine sand flies by Leishmania (Viannia) was conducted in a focus of cutaneous leishmaniasis in Piçarras, on the northeastern coast of the Brazilian state of Santa Catarina. In total, 562 female Nyssomyia neivai were collected by miniature light traps near houses, separated in 61 pools and examined by PCR and Southern blot hybridization. Eight pools, four of them from the same light trap/night, were positive. This is the first finding of natural infection by Le. braziliensis of adequately identified Ny. neivai in Brazil. In this preliminary observation we observed the abundance and predominance of Ny. neivai among the captured phlebotomine species (98.5%), indicating that Ny. neivai may be the dominant vector of Leishmania in the subgenus Viannia in this area.