Peruvian Terns Sternula lorata breed in the sand desert plains of the coast of Perú and northern Chile. Because of their long-term population decline, Peruvian Tern is categorized as 'Endangered' on the IUCN Red List. The observations that formed the basis for that decision were made in the 1970s and 1990s. In this study, we compile information on distribution, numbers, habitat use and threats of Peruvian Terns that has become available between 2003 and 2008 from 14 localities on the Peruvian coast. Peruvian Tern sites are located between the mangroves of San Pedro de Vice in the north (5o31′S) and the wetlands of Ite in the south (17o 56′S). From the 14 locations, five are reported for first time: Virrilá, Eten, Huanchaco, isla Mazorca and Ite. There were only four active breeding sites: Pacasmayo, Paraíso, Pampa Lechuzas and Tres Hermanas-Yanyarina; however, some localities were visited outside the breeding season and should be surveyed between October and February to search for nests. The presence of 283 individuals was confirmed at the 14 sites in an area of approximately 1,388 ha (which represents only 0.35% of the total suitable area for nesting along the Peruvian coast). Thus, the number of Peruvian Terns in Perú should increase with systematic surveys. Here for the first time we report the importance of wetlands for the Peruvian Terns (43% of the sightings occurred in this habitat). Wetlands can offer optimal conditions for feeding, but the cost of using them is becoming higher with a sharp increase of human expansion into coastal areas and urban development around wetlands. We identified the following threats affecting Peruvian Terns on their feeding and breeding grounds: 1) recreational activities; 2) off-road driving by fishermen and tourists; 3) wetland pollution and water use for irrigation; 4) conversion of desert plains to agricultural land; 5) management of wetland water levels; 6) presence of feral cats and dogs, and 7) oil exploration on the desert plains. These adverse factors can be eradicated by the protection of tern sites and public awareness and education. Conservation actions, monitoring and research priorities are suggested. © 2009 BirdLife International.