An ageing society is characterized by a growing proportion of the retired to the active working population. Ageing affects virtually all societies today, but more so the industrial countries which have generally experienced it over a long period, and for which further pronounced ageing is projected over the next four decades. Concerns about the challenges posed by ageing populations have moved to the forefront of the public policy debate in many countries. This paper attempts to respond to some of these concerns, focusing in particular on the fiscal sustainability of public pensions schemes in industrial countries.