Abstract The beginning of the 21st century was very compulsive concerning to the Spanish urban dynamic. The main cause has been the explosive urban growth that took place between 2000 and 2008 and its next stoppage by the Great Recession. The article analyses this process centred on medium-sized cities and their respective crowns within the national context. A comparative study of the evolution of the population and the constructive units in medium-sized cities and their urban areas was presented. The sources used are the Municipal Register of Inhabitants and the Real Estate Cadastre. The research is carried out by a deductive method. The results obtained show a disparate response of Spanish cities within the common pattern marked by the tipping point of the crisis, with a general context of growth until 2008 and subsequent fall. In addition, there is a different behaviour of urban growth in relation to proximity to a large metropolitan area.