The impact of population ageing on the social budgets of the future is a phenomenon confronting many of the world's wealthiest and most advanced nations. The impending retirement of the 'baby boomers' has raised concerns about the inadequacy of budgetary frameworks (both conceptual and real) to fulfil the financial commitments of demographically sensitive programs, namely old age pensions. Pension schemes represent, by far, the largest social welfare commitment of first world nations. Old age pensions are also demographically sensitive. Furthermore, pension systems play a crucial role in alleviating poverty, in recognising the previous contribution of an individual and in maintaining of the social and economic wellbeing of democratic polities. The financial stability of pension schemes and the ability of governments to meet future commitments will become significant issues of public policy as the pressures from population ageing intensify. Yet, committing resources, or budgeting, for longer-term pressures is an inherently problematic exercise both from an intellectual and a practical perspective. For long-term resourcing to be successful it requires perfect foresight and a level of political commitment that typically eludes most politicians and governments. Longer or medium-term budgetary pressures are often ignored or avoided until they impact on the immediate chances of either fiscal or electoral success. As such, societies face the prospect of looming financial burdens, but only have a box of short-term tools at their disposal and a limited body of scholarship to guide them through this ticking political 'time bomb'. This research tackles a significant omission in the existing literature on budgeting, public policy and social welfare, by proposing a conceptual framework for the anticipation, conceptualisation and analysis of future budget pressures. In doing so, it brings together analytical frameworks of government budgeting and social policy from a number of disciplinary areas and weaves them into a conceptual framework that allows for diagnostic and prescriptive analysis of budgetary pressures within a particular policy/spending area. The framework is also compatible with existing budgetary frameworks and decision-making processes. Through the analysis of the old age pension systems in Australia, Canada and Sweden this thesis makes an important contribution to the understanding of how demographic transition will impact on the future stability of pension schemes. The thesis contends that ageing populations will place significant pressure on each pillar of the pension system to meet its future financial commitments. This pressure will, in turn, have important implications for national budgetary processes and old age pension policy over the coming decades. In particular, governments will be required to implement a range of techniques that sit both within and beyond the traditional bounds of most budget processes. It will be imperative for researchers to explore the complexities and political possibilities of budget reform and to search for ways in which the longer-term needs of society can be adequately satisfied through the budget process.