Based on dental and cranial characters, cladistic status of Leontopithecus within the family Callitrichidae and its interspecific relationships are analyzed. Leontopithecus is the closest genealogical relative of CallithrixCebuella because Leontopithecus has two significant apomorphies in common with Callithrix-Cebuella; the septa in the tympanic cavity and the quite reduced hypocone on M1. Since Leontopithecus chrysopygus and Leontopithecus rosalia share an apomorphy, round-shaped P², with each other, Leontopithecus chrysopygus is more closely related to L, rosalia than either is to L, chrysomelas. On the basis of the interspecific relationships of Leontopithecus and Callithrix, the refuge for L. rosalia is considered not the Bahia refuge of KINZEY (1982) but the Orgaos refuge of JACKSON (1978).