Questions like aging population in developed countries, permanently low birthrates or immigration are well known from newspaper articles at least what the headlines concerned. The study attempts to examine these questions in scientific way and also to show the immigration and integration policies of the most concerned European countries. In Europe, national cultural identity is traditionally strong and many are afraid that a more open immigration policy will make welfare systems financially collapsing. The labour market in the US is open, and it seems, that the "American Dream" attracts more immigrants but the US – in European sense – never was a "welfare state". Nevertheless, the US model still has lessons for Europe if it wants to save its welfare systems.