The demographic regime in western Europe and many other countries of the developed world is now very different from that of 30-40 years ago and is continuing to evolve. At the same time, settlement systems have been altering significantly in spatial structure, notably in terms of the emergence of polycentric urban configurations. This paper examines the nature of these two sets of changes and searches for linkages between them. First, it outlines the main features of the changing demographic regime. Secondly, it attempts to identify what constitutes 'polycentric urban regions' as opposed to traditional monocentric structures. Thirdly, it assesses how recent demographic developments relate to traditional urban structures and discusses whether they are more conformable with polycentric urban forms.