Multivariate discriminant analysis was employed to discriminate on a morphological basis females of 3 closely related sand fly species, Lutzomyia townsendi (Ortiz), L. spinicrassa Morales, Osorno-Mesa, Osorno & Hoyos, and L. youngi Feliciangeli & Murillo. Principal component and canonical discriminant analysis compared a set of 31 morphological characters measured from known specimens to detect differences among the 3 species. A subset of 6 characters separated the 3 species with a high level of confidence. A simple method is presented to identify an unknown specimen as L. townsendi, L. spinicrassa, or L. youngi using these 6 morphological characters.