This chapter focuses on one fundamental aspects of an ageing population — how to pay for old age, individually and collectively. It also presents a study of the history of old age support in the UK and US and concludes that despite the quite different beginnings of the public pension and social security systems, government policy in both countries has become similarly locked in to a set of institutional arrangements which were devised to respond to immediate social and economic problems, but which have acquired a rationale and a dynamic of their own.