The article analyzes the Croatian population to understand the effects of decreasing fertility rates and an aging population. By using demometric methods, the researchers studied fertility levels, population stability, and hidden population momentum. They also calculated the Bongaarts-Feeney quantum and tempo of fertility, as well as the Coale-Trussell fertility method. The intrinsic growth rate of a stable population model was determined, and population momentum was examined to understand changes in population size. These methods were also applied to other European countries for comparison.