The purpose of given research is to analyze the impact of demographic changes on the market of labour force and the financial stability of state social insurance in the Republic of Moldova. Population decline, including through labour migration, and ageing population process affect the age and sex structure of labour force, its reproduction and the quality of labour market. Demographic ageing of population is accompanied by an increase in the number of age pensioners, which on the one hand contributes to ageing of labour market and reducing its competitiveness, which requires additional costs for retraining of elder labour force to support the labour market and, on the other, leads to increase in social insurance budget expenditures on age pensions and other social benefits to support and care for the elderly population. As a consequence of the above processes, there is financial instability in the social insurance budget as a result of reduction in contribution income from the employed population. Given article presents the results of calculations of the losses of social insurance revenues from the reduction in the number of employees, which is a challenge to improve the effectiveness of public policies. Based on the results of research, conclusions and proposals to improve the situation on labour market in condition of demographic changes and increase the financial stability of the social insurance system were elaborated.