The black-breasted hillstar is a species of hummingbird in the family Trochilidae. It is found in scrub at altitudes of 3,500 to 4,400 metres in the Andes of central Peru. Unlike the other hillstars, the tail, chest and belly of the male black-breasted hillstar are almost entirely black . The females are more bronze and grey-ish brown. This species shares a lot of common traits with the Andean hillstar but does not have a white base on its tail.