The forecast changes in the total population, the labour force and their age structures are alternatively sources of concern and optimism: fears about pension funding, fear of negative effects on the economy's buoyancy, and, conversely, the hope of a sharp improvement in employment prospects. One of these concerns, the pensions balance, has been studied inside out and is well known: population ageing raises a definite problem from the point of view of the trade-off between the level of contributions, the relative purchasing power of pensioners, and the retirement age. However, the other consequences of demographic changes are less often explored, especially the effects of the relation between demographic change and labour market imbalances. This relation is complex. There is little doubt that the trend reversal in the labour force in the middle of the decade will constitute a major break. Yet there is still great uncertainty as to the form of the accompanying changes, both because demographics are merely one determinant among other macroeconomic patterns and aggregates, and because the channels via which these demographic variables influence others are many and sometimes contradictory. The only certainty is that the turnaround in the labour force will not alone guarantee a spontaneous return to full employment.