Issues related to the cost-effectiveness of biodiversity conservation policies have not yet been prominent in European conservation research and policy-making. Nevertheless, there is a small but growing literature which analyses such cost-effectiveness issues on both a conceptual and an applied level. The article reviews this literature, and focuses on reserves and compensation payments for conservation measures as the two most relevant conservation policy instruments in Europe. Progress has been achieved in understanding the cost-effective allocation of conservation measures and reserve sites, and further advances can be expected by integrating knowledge from ecology and the neoclassical analysis of policy instruments. Research on cost-effective monitoring, enforcement and decision-making has addressed selected issues such as designing incentives for farmers to reveal their conservation costs to the regulator. However, issues with high relevance for European conservation policy such as the cost-effectiveness of compensation payments for results and implementation problems related to the network NATURA 2000 have been neglected.