In the next decades, developed countries will experience dramatic changes intheir demographic trends. The retirement of the wide baby-boom generations, theincrease in life expectancy and the decline in fertility ratios are likely to modifythe size and the age-structure of their populations. The expected population ageingin European countries will burden the pension systems, especially whereverthe pay-as-you-go pillar is predominant. Recently, migration has received a widespreadattention as a solution to expected population decline and ageing in thesecountries. The flow of (young) migrants to developed countries is perceived asa means to alleviate the financial burden of pension systems. The aim of this contributionis to clarify the issue of aging on labour and capital markets in a macroeconomicperspective. A special attention is given to the risk of imbalances in thefinancing of social protection in the context of demographic ageing.