EN
The aim of this paper is to provide a statistical description of the demographic structure of the members of the Open Pension Funds as well as its dynamics. The paper also describes the process of ageing of the Open Pension Funds' members taking into account the whole operating period of the funds. Selected demographic measures were used to analyze the demographic structure changes of the funds' members in total and by sex and age. To describe the process of ageing some alternative measures based on central moments of the empirical distributions were employed. The analysis reveals a significant differences of the process of ageing between the funds.