With ageing development needs for its thorough analysis increase, especially for Spain, which is rather demographically old country. Population ageing is a multifaceted process, it affects all sub-populations, including labor force and sub national administrative units. Spain consists of 17 autonomous regions. Regional differences in demographic indicators affect both age structure of the whole population and age composition of working age population. This paper makes a comparative analysis of dynamics of major age groups proportions (children, working age population, population 65+) and of changes in age structure of working age population (divided into groups 20-34, 35-49, 50-64, designated wa-i, wa-ii, wa-iii) in Spain and Autonomous regions since 1991. The study is based on censuses and micro-data on vital events. Computations were made in Excel. It was found, in particular, that proportions of population aged 65+, as well as proportions of wa-iii, increased for Spain and all autonomous regions. Ranges of changes in the proportions of major age groups for each year for total populations and working age populations were detected. Thus, maximal values of wa-iii proportions were observed in Aragon, Asturias and Galicia, minimal ones – in Balears, Canarias and Murcia; growth (relative to 1991) in the proportion of wa-iii varied from 4% (in Castilla-La Mancha) to 30% (in Pais Vasco). The study revealed similarities and diversities in dynamics of ageing indicators for Spain and autonomous regions. Results of the study may be helpful to increase older age groups' potential.