Forthcoming decades in Western Europę will be a period of population implosion and
progressing ageing of population. One of the counteractions against these disadvantageous
demographic tendencies is mass immigration. The article presents estimations
concerning the immigration scale that is necessary to keep Europe competitiveness,
showing that in many countries the share of the immigrants and their descendants in the
first generation would be 1/3 of the whole population. Next, the author focused on the
social conseąuences of mass population inflow from the non-European countries —
especially taking into consideration potential sources of social conflicts.