In the sixty years from 1930 to 1990 the population of Latin America more than quadrupled – from approximately 110 million to almost 450 million. Population growth was higher in Latin America than in any other region of the world except, marginally, Africa (see Table 1.1). Though average population density in Latin America remained low in comparison with other areas, this was misleading because of the way in which population was distributed. The bulk of population increase after 1930 occurred in cities. While export-led economic growth in the period 1870–1930 had stimulated the growth of a few cities, principally ports and administrative centres, Latin America was still in 1930 predominantly rural. About 17 per cent of the population resided in cities with 20,000 or more people. During the following half century city populations increased more than tenfold, accounting for two-thirds of total population growth. Internal migration (fed by a high natural increase in the population of rural areas) was responsible for most of the difference between rural and urban population growth and was a major demographic feature of the inward reorientation of the region's economy, which experienced a decline in the share of agriculture and an increase in the share of urban based manufacturing and service activities in total production and employment.

Population trends after 1930 contrasted in several important respects with those of the period before 1930. Immigration had had a significant impact on population increase between 1870 and 1930, although it was concentrated in a few areas: Argentina, southern Brazil, Chile, Cuba and Uruguay. Population growth rates elsewhere were generally lower.