Two new Andean species of the genus Brachistosternus Pocock from southern Peru and northern Chile are described: B. titicaca sp. n. from the Titicaca basin (Departamento Puno, Peru), at 3850-3900 m, and B. quiscapata sp. n. from Departamento Tacna (Peru) and Provincia Arica (Chile), at 3100-3400 m. Both species belong to the subgenus Brachistosternus (Leptosternus) Maury. They are related to the Argentinean species B. (L.) intermedius Lönnberg and B.(L.) montanus Roig Alsina. Comparisons between these four species are provided, including a combination of characters: length/width ratio of metasomal segment V, number of setae of metasomal segment V and tarsus III, ventral pigment of metasomal segments, and some details of the hemispermatophore morphology (distal lamina and cylindric apophysis). The presence of the subgenus Brachistosternus (Leptosternus) in Peru is therefore confirmed.