Migration to Argentina has been heavy in the past, especially from Spain and Italy. Under the rule of Juan Domingo Perón, immigration was restricted to white persons, exceptions being made for relatives of nonwhites (Japanese and others) already resident. More recently, immigrants from across the border in Paraguay have numbered at least 600,000; Bolivia, 500,000; Chile, 400,000; Uruguay, 150,000; and Brazil, 100,000. Some 300,000 illegal aliens were granted amnesty in 1992. Foreigners, on application, may become Argentine citizens after two years' residence. A total of 16,738 were naturalized in 1991, of which 13,770 were from other American countries. In 2000, Argentina's refugee population was estimated at 2,400. Few Argentines emigrated until the 1970s, when a "brain drain" of professionals and technicians began to develop. In the mid-1980s, some 10,000 of the estimated 60,000 to 80,000 political exiles returned home.
Of much greater significance to Argentina has been the tendency for workers in rural areas to throng to the cities. This had particular political and economic overtones during the Perón regime of 1946–55. Perón's encouragement of workers to move to Buenos Aires and surrounding industrial areas drained rural areas of so many persons that agriculture and livestock raising, the base of Argentina's wealth, suffered severely. Moreover, the inability of the economy to absorb all of the new urban masses led to a host of economic and social problems that still besiege the nation. Both the federal government and provincial governments have since vainly entreated aged workers to return to rural areas.
There has been a significant increase in asylum claims in recent years, beginning the latter half of the 1990s. As of September 2000, there were 3,000 refugees and asylum seekers, of whom 1,300 received counseling and assistance from UNHCR. Most were from Peru (48%) and Cuba (12%), but there were also more than 30 other nationalities from Latin America, Eastern Europe, Africa, and Asia. In 2001 there were 0.7 migrants per 1,000 population.