The fiscal impact of predicted changes in the size and age structure of the Irish population represents a major challenge for policymakers. This paper estimates the costs, in real terms, attributable to demographic changes over the next two decades, on the public health system. A more holistic model is also presented, incorporating demographic, income and residual growth factors. The model produces forecasts of public current health expenditure in real euro terms and as a proportion of GDP in 2035. The paper emphasises the need for greater investment in the future to accommodate the healthcare needs of a changing population.