In South America, Kelp Gulls (Larus dominicanus) breed from Chilean Tierra del Fuego north to Río de Janeiro, Brazil, on the Atlantic coast and to Piura, Peru, on the Pacific coast. This review presents the first synthesis of information on the distribution and size of Kelp Gull colonies at the country level in coastal environments of Uruguay, Chile and Peru; provides an update on the breeding situation of the species in Brazil and Argentina; and allows the first evaluation of the overall coastal breeding population in South America. The breeding population in South America is now estimated to number at least 160,000 pairs. The largest population (at least 106,000 breeding pairs) is found in Argentina. Colonies of more than 1,000 pairs are uncommon. Population trends differed among coastal sectors, and important increases in numbers and formation of new colonies were only observed in Argentina. Available information suggests that predictable and abundant anthropogenic food subsidies, such as fishery discards and urban waste, are key factors contributing to the population growth in some coastal sectors. There is no strong evidence that Kelp Gulls are currently expanding their breeding range. However, given the population expansion in some areas and the potential conflicts with humans, ongoing monitoring efforts and population evaluations are necessary as they will provide the information required to support management decisions.