The Philippine endemic genus Bullimus is currently considered to include three species, one each from the Late Pleistocene islands of Greater Mindanao, Greater Luzon, and Camiguin. We describe a fourth species, Bullimus carletoni, new species, from the Caramoan Peninsula in southern Luzon based on analyses of molecular and craniodental data. Molecular data suggest that Bullimus colonized Luzon from the southern Philippines and began diversifying on Luzon by ca. 232 kya. This species is associated with partially disturbed forest habitat over limestone and ophiolitic soils, where it is active primarily on the ground at night. Recognition of this species raises the number of endemic mammals on the Bicol Peninsula of southern Luzon to six, emphasizing its importance as a center of endemism.