Abstract. In this article, an analysis of the structure and number of population in the context of demographic changes was carry out. The evolution of the ageing process, changes in number and structure of population, including the main age groups and in the aspect of men-women were examined. The Republic of Moldova, similarly to many countries, is undergoing a process of demographic ageing, the consequences of which are challenges for the policies and affect to the development of economy, the growth of expenditures for health, pensions and social protection, the vulnerability of elder population and the risk of poverty, what confirms the relevance of the topic. The purpose of the research is to assess the tendencies in number and structure of population, including the main age groups and age pensioners by gender, as well as to elaborate a methodology and projections of age pensioners for the long term. For the research, a systematic approach and such methods as comparative analysis, graphical method of interpreting tendencies in dynamics and demographic models were used. Quantitative and qualitative assessment the results of projections the elder population provided an opportunity to substantiate the tendencies of irreversible nature of the ageing process and offer some recommendations for adaption and modernization policies to new demographic realities in conditions of ageing challenges in economic and social systems.The article was elaborated within the framework the State Program Project (2020-2023) 20.80009.0807.21 “Migration, demographic changes and policies of stabilization the situation”.