The black-headed marmoset (Mico nigriceps) is a marmoset species endemic to Brazil. It inhabits humid tropical rainforest, mostly second growth and edge; the distribution is not exactly known but is thought to be Rio dos Marmelos in the north and east, Madeira River in the west and Ji-Paraná River in the south. The threats are not exactly known but it may be near human traffic including the Trans-Amazonian Highway where cattle ranching and logging is occurring.