Many of the people of the territory, who devoted themselves mostly to agriculture and livestock, gradually abandoned the area, heading towards urban areas, much more prosperous. This situation was further aggravated at the end of the Spanish Civil War, with a progressive rural emigration. During the 1960s and 1980s, large urban centres and provincial capitals suffered a slight demographic increase due to a thorough urbanization process, although, despite this, the Castilian-Leonese area continues to suffer serious depopulation. Only the Provinces of Burgos, Valladolid and Segovia are gaining population in recent years.

There is also an increase in the population of metropolitan areas around cities such as Valladolid, Burgos or León. Due to this phenomenon, cities such as Laguna de Duero or San Andrés del Rabanedo have seen their population increase rapidly in a few years. The metropolitan area of the city of Valladolid is, by far, the largest in the autonomous community, with more than 430,000 inhabitants.

However, in absolute terms the autonomous community is losing population and aging. In 2011, it was one of only four autonomous communities that lost population along with Asturias, Galicia and Aragon.