According to recent research, modern development in Croatia is burdened by distinct regional disparities. As differences in socioeconomic development are the key generator of spatial mobility of the population, this is reflected in the atrophy of demographic resources of less developed areas, and consequently in the destabilization of their population. Due to the connections between economic and demographic development, the paper examines demographic resources as an indicator and factor in the disparities occurring in the regional development of the country. Demographic resources in 2001 and 2011 on three hierarchical levels of regional development and four spatial categories are explored, as well as the composite index of development of counties in 2013. The research process includes the calculation of synthetic indicators of demographic potential – the index of demographic resources (ider) and its evaluation within the typological scale of six threshold values. The research results show that: first, Croatia has a highly uneven spatial distribution of demographic resources; second, more than half the number of the counties belong to the first development category, and only three counties to the fourth development category; third, regions in the fourth development category are characterized by favorable demographic resources, while areas in the first category are characterized by weak demographic resources; and fourth, structural and dynamic characteristics of the index of demographic resources clearly indicate specific development problems in certain parts of the country.