This paper studies the relationship between an ageing society and voter preference for financing public expenditures with debt versus income taxation. We focus on advanced economies and OECD members where ageing is relatively severe, the political process is more democratic, and economic institutions are subject to electorate scrutiny. Since there are no international data sources available for the median voter age, one of the contributions of this paper is the construction of a median voter series for the countries included in the study. The sample period covers 30 years, from 1980 to 2010. The panel estimates confirm the Brennan hypothesis (Const Polit Econ 23(3):182–198, 2012). A 1-year ageing of the median voter increases the public debt-to-GDP ratio by the order of 4.5 percentage points.