The Katowice conurbation is an example of a typical old industrial region in Central and Eastern Europe, whose socioeconomic transformation, initiated after 1990, has led to spatial and functional changes. The aim of this article is to present the suburbanisation process in the Katowice conurbation based on demographic changes and an analysis of migration flow. This process has been taking place in the area since the 2000s and takes on the shape of a multi-centre development of newly created individual and developed housing zones (both in the core and in the suburban area of the conurbation). Since 1990, the cities of the Katowice conurbation have been undergoing a process of shrinking. This process is manifested in the decline in number of urban residents in the years 1991–2016, amounting to 366 thousand people. Moreover, the cities face numerous social, economic and spatial problems. Since 1995, simultaneous with the shrinking of the cities of the Katowice conurbation, there has been an increase in the number of inhabitants in its suburban areas (since 2004, the trend has continued to be positive). Population increases have also been recorded in some inner-city zones of the conurbation. The suburbanisation process in the outer zone of the conurbation includes, in particular, the communes located north and south of the cities constituting its core, including the communes of Ożarowice, Psary, Mierzęcice in the north and Mikołów, Orzesze, Wyry in the south-west. On the other hand, the areas of intense inner-city construction development, located in the areas of the Katowice conurbation core, which are attractive in terms of environment and transportation, are undergoing so-called, “internal suburbanisation”.