Until the end of the era of Iberian domination, only the Spanish and Portuguese were admitted to their South American colonies. The rigid exclusion of all other foreigners had but few exceptions, though a small number of non-Iberian Europeans settled as a result of illegal or tolerated immigration. Most of the Spaniards came from Castile and the southern regions. Little is known about the principal regions from which the Portuguese came. It is estimated that the total number of licencias (authorizations to emigrate) granted by Spain was about 150,000 for the entire colonial period, which lasted from the 16th to the 19th century; it is possible that the number of illegal immigrants also approached this number. Of these, no more than two-fifths of the emigrants went to South America. Up to one million Portuguese may have migrated to Brazil, drawn primarily by a gold rush in Minas Gerais in the 18th century.

A few African servants accompanying the early Spanish or Portuguese explorers were the first slaves to enter the continent. Larger-scale importation of slaves from Africa developed after the slave trade was established early in the 16th century, though reliable quantitative information is lacking.