The brain cell karyotypes of six New World sand flies are described and compared. Lutzomyia trapidoi has three pairs of chromosomes, 2N = 6. The other species, L. gomezi, L. erwindonaldoi, L. carmelinoi, L. walkeri and L. columbiana, have four pairs of chromosomes, 2N = 8. No heteromorphic chromosomes were observed. Cytogenetic similarities among sand fly species are discussed.