The article presents a contemporary, multifaceted analysis of changes occurring in post-industrial sites within Polish cities. The research focuses on the demographic, morphological and functional changes observed in selected brownfields in Wrocław and Kraków. The findings indicate that such areas in large post-socialist cities are currently undergoing a period of intensive transformation, primarily characterised by increased land use intensity and functional changes. To preserve the cultural heritage of these areas, it is essential to continue monitoring these transformations in the future.