Population is one of the key figures of general social and economic growth, therefore it is impossible to predict future developmental perspectives without considering and valuing demographic aspects. In the thesis was conducted an analysis of demographic aspects for United States of America, Japan, Australia, Canada, European Union with a special emphasis on Croatia. The analysis of demographic aspects showed: The fertility rate is deep underneath the referential value in order to allow just a generational shift, whereas the birth rate is decreasing, which can be linked to the decrease of the fertility rate. Furthermore, the mortality rate has become inversely proportional to the birthrate. The expected lifespan is also increasing, while the number of immigrants is decreasing. The rate of age dependency of the elderly is increasing as the population is becoming older. Due to such demographic changes, the fiscal system, i.e. the financial system, is increasingly burdened. In the long run, states will have to secure more means for health care, social systems and retirement. In Croatia the situation is similar like other analyzed countries, so we can conclude that fiscal system is becoming more burdened as the population ages and more funds are being spent on the demographic consequences of population ageing.