The Andean night monkey Aotus miconax is found only in Peru's northeastern cloud forests, and is one of the country's three endemic primate species. Very little is known of this species; today largely limited to the records of Butchart et al. (1995) and a few museum specimens. Between 2005 and 2007, we observed A. miconax in various localities in the regions of Amazonas and San Martín, and recorded what we could of its natural history, distribution and conservation status. The Andean night monkey was observed to live in groups of two to four individuals, using sleeping sites at heights of 6 to 9 m. We have confirmed the presence of the species in 10 additional localities in Amazonas and San Martín, all between 900 and 2,788 m above sea level. It was recorded in various forests types, from primary to relict. Even though it is not hunted directly and can survive in disturbed habitats, the extremely high rate of deforestation in this area is threatening its long term survival. Research on the biology, natural history and ecological requirements of this species are much needed.