After the decimations that occurred mainly at the beginning of the colonial era, also for the diseases introduced by the conquistadors (the Indian population at the time of the Inca empire was variously estimated at 6-7 and even more million residents), the country’s demographic developments had their first strong impulses only in the twentieth century: suffice it to say that in 1850 there were in Peru, according to the data of the first census, 2 million residents, which rose to 2.7 million in 1876. The subsequent census, carried out only in 1940, gave a population of over 7 million residents. The increase in the last decades of the twentieth century was very strong, reaching the over 26 million recorded in 2005. The growth of the nineteenth century was due in part to European emigration (which had Spanish, German, Italian etc. as protagonists) and Asian (Chinese, Japanese), although not as strong as in other Latin American countries, and partly due to improved hygienic conditions, which have reduced infant mortality. The average annual growth coefficient between 1990 and 1995 was 2%, that is, attested to the typical South American value, which fell, as happened in neighboring countries, to around 1.1% in the period 2005-2010.

However, the demographic indicators describe a different situation compared to other Latin American states, such as Argentina, Brazil, Colombia, where birth rates have dropped drastically. In fact, as a country of South America defined by ethnicityology, com, Peru stands out for its high birth rates (20 ‰ in 2012) accompanied by low mortality rates (5.3 ‰ in 2012), which in fact make the Peruvian population a young population: about 30% have less than 15 years. About half of the population is represented by Indians, settled almost entirely on the highlands, followed by mestizos (31.9%), which mainly populate the coastal centers, by the Creoles (12%), who represent the elite of the country and live in the cities, and by small minorities of blacks or mulattoes settled in the coastal areas. The Indians are predominantly Quechua (47%) while the aymará component is much less numerous (5.4%). The defense of indigenous communities and the safeguarding of ancient local traditions clash with the needs of the oil companies that have been exploiting the fields in the northern regions of the country for years. The 1993 constitution abolished the rules that protected the rights of communities over the lands they inhabited, making privatization easier. More generally, the Indians have greater difficulties in accessing health and education services. As for the distribution of the population, it can be said that it increasingly depends on the development of urbanism. This in fact is poor in the Andes and is instead conspicuous on the coast, where Lima and the entire metropolitan area, with its over 10 million residents, represents a typical South American metropolis, the third for number of residents, which alone hosts more than a third of the entire Peruvian population. Its department has a density of 274 residents / km², eleven times higher than that of the national average (24 residents / km²).  In the Andes the densities are much less high; relatively well populated are the valleys that slope down from the Andes towards the coast, especially at a certain altitude, precisely around 2000 m. Also on the opposite side the 2000 m represent a populated altitudinal plane; further down we pass to the empty spaces of the lowland, where there are on average 1-4 residents / km². Outside the cities, on the plateau the population lives mainly in the small Indian village of shepherds and peasants (some settlements go up to 4000 m of altitude), consisting of small huts of adobe, often in the center of a courtyard. In some areas there are small scattered nuclei, as in the western valleys. Here, often, villages have sprung up around the old haciendas founded by the encomenderos, the large Creole landowners who subverted, with the land regime, the very distribution of the settlements as well as the original agricultural landscape.

The top of the local organization are the centers that have the various social services: the church, the market, the outpatient clinic, etc. In the coastal area the oasis centers are surrounded by scattered nuclei and houses, according to characteristics that are well expressed even on the outskirts of Lima. The departmental capitals have a fundamental role in the territorial organization; they act as coordinating centers of territories of very different dimensions according to the zones and some are now populous cities, sites of industrial activities. Urbanism is now on the whole developed and continuously increasing: the percentage of the urban population is equal to 75.6% of the total, against about 47% in the 1960s. Since the 1980s there has been an exodus from rural areas to the outskirts of large cities, especially the capital, following the attacks of Sendero Luminoso, only a small part of which subsequently returned to their homes. The rapid growth, however, has affected almost exclusively the coastal cities and especially Lima, now welded to Callao, its port, is formed by an extensive succession of barriadas that reach the first hills from the sea. The city, which was one of the first (1535) and most important ones founded by the conquistadors in South America, has now lost its original colonial characteristics in its center and has taken on the anonymous face of Latin American cities. However, it is a very active metropolis, not only for its capital functions but also for its economic and industrial activities; it has promoted, in addition to the growth of Callao, that of other coastal resorts, especially seaside resorts (San Miguel, Miraflores, etc.).