Red-legged Cormorant Phalacrocorax gaimardi, considered Near Threatened, is one of the most conspicuous seabirds on the south Pacific coast, although its current status is unknown. During spring and summer of 1998, 1999 and 2000 we surveyed Red-legged Cormorants along the Chilean coast. Survey portions of the coast were chosen based on published information, and discussions with local people. Nesting sites were distributed from Arica (18°30′S) to the Peninsula de Taitao (46°25′S). We found 40 breeding areas with at least 54 colonies, ranging from two to 964 nests. Colony size (as number of breeding birds) was larger in the south than in the north. Isolated pairs or small colonies were found in the northern and central part of Chile. The southern coast (Xth Region) held most colonies, including the largest one with approximately 1,000 breeding pairs, suggesting it is a critical area for the species. We estimated the Red-legged Cormorant population in Chile to be between 5,018 and 5,218 breeding pairs. The Xth Region holds approximately 80% of the whole Chilean population. Factors affecting the breeding distribution of this bird in Chile include coastal development, nesting habitat availability and the occurrence of El Niño (ENSO) events. Human consumption may be important locally, mainly in the south. Chile holds more than 70% of the world breeding population, estimated at fewer than 15,000 individuals. The Peruvian population has declined during recent decades, and the Argentinean population seems to be small and stable. Thus the Chilean coast, particularly the Xth Region, is a critical area for the conservation of this species.