We present information regarding to the richness, distribution and mammalogical research in the Department of Putumayo. A total of 154 species of 13 orders and 37 families were registered in the Department. Chiroptera, Rodentia, Carnivora and Primates were the most diverse orders with 66, 24, 19 and 15 species. The Alto Putumayo biogeographic District presents the highest richness with 136 species, while the Napo Humid Forest was the richest Ecoregion with 131 species. Puerto Leguízamo was the Municipality with the highest number of species with 100. We highlighted the absence of regional studies and the poor knowledge associated to mammals, generated in this sector of Colombia.