The paper discusses the attempt undertaken for to review demographic conditions of the ageing process of the Polish population, as well as for to get to know the mechanism of this process and to formulate next a diagnosis of the present state and, finally, to determine a perspective of development of this process in relation with long-term prognoses. The study is preceded with a comment on general trend of the ageing of populations in Western Europe countries where this process has begun much earlier as a result of advanced demographic transformations in these countries and, consequently — deep changes within the populations. The process of the ageing causes serious changes in the structure of the population age; the changes are con...