Following distinctive trends toward urbanization and suburbanization, spatially heterogeneous demographic dynamics are increasingly reflective of different development trajectories at both urban and metropolitan scales. A comprehensive investigation of population trends along homogeneous cycles of urban expansion–with identification of the most relevant factors of growth and change–is still lacking for several European cities. On this point, the present study investigates spatio-temporal patterns of urban expansion in 174 metropolitan regions of Europe, comparing population trends in inner cities and suburbs during a relatively long-time interval (1950-2000). A mixed (parametric/ non-parametric) statistical approach was developed with the aim to profile the specific socioeconomic context underlying population growth (or decline). A comparative analysis of population trends in inner cities and suburbs allows identification of similarities and differences in urbanization patterns and processes across Europe and contributes to define metropolitan clusters associated with a specific background context. The empirical results of this analysis give a more complete representation of contextual factors of population growth and decline in European cities, outlining the increased demographic polarization in inner cores and suburbs during the earlier phases of urbanization. Evidence for higher heterogeneity and fragmentation of long-term population trends during the late phases of urbanization brings further insights in the debate over the future development of contemporary cities.