EN
The aim of the study is to compare the effect of changes in fertility and mortality on population aging in Poland by provinces. The following hypotheses were verified:(1) the main factor affecting the aging of the population in Poland is the decline of fertility, (2) lengthening of life expectancy of elderly people has a weaker effect, due to the lower rate of decline of mortality in this population, (3) aging of the population in Poland varies depending on the place of residence. To verify these assumptions, considered two types of scenarios. The first one shows the evolution of population structure, individual regions, assuming a constant level of fertility, which are assigned to hypothetical changes in mortality. In the second indicated how changes in population structure, with varying fertility attributed to a constant level of mortality.