The main aim of the research has been to characterise changes the urban functional areas in Poland over 2002–2017 period. The research was based on J.W. Webb’s population development types method enabling to identify links between natural growth and the migration net. A wider analysis concerned components of real increase which, through feedback, influenced level and population dynamics in these areas. Results of the study showed the diversity of demographic processes within Polish urban functional areas as well as in their cores, which will shape different processes in those areas in the future.