OECD countries face the multiple challenges of rapidly ageing societies with the associated rise in chronic diseases and the ever-present threat from new or evolving communicable diseases. This is within the context of seeking better value for money from the health sector. While a growing body of evidence shows that many health promotion and disease prevention measures can improve health outcomes at relatively low cost, less has been documented - in an internationally comparable way - on how much countries actually invest in such activities and the drivers of prevention spending over the years. This is particularly pertinent in the context of fiscal sustainability and tight public budgets. Using newly available data from across OECD countries, this study examines the differences in spending on prevention both at an aggregate and detailed level. This analysis brings a fresh perspective and raises questions as to the optimal resource allocations within the sector. Time series data is also scrutinised in conjunction with collated policy and public health developments from a number of countries to try to identify some of the drivers behind the observed prevention spending trends. In doing so, directions for further improvement in the underlying data as well as policy implications are discussed.