A high level of mental health will support the EU in becoming more knowledge-based, competitive and socially cohesive. However, the EU is far from such a position, with mental disorders accounting for 20% of all European ill-health and premature death, at a cost of some 3%-4% of GDP. The WHO Helsinki Action Plan for mental health called for an integrated set of databases to provide the evidence for health promotion and protection to be integrated into mental health policy in relevant environments and sector s. Gathering and building on world-wide and European research and evidence, DataPrev aims to encourage a single EU playing field and to add value to EU and country policies by deepening the understanding and enhancing the evidence base in policy research f or mental health promotion and protection.DataPrev will develop a standardized protocol for collecting and appraising programmes for infants, children, working age and elder populations, describing and synthesising the evidence base and describing program me outcomes for increased cognitive and social and emotional development, reduced mental ill health, decreased psychiatric symptoms and disorders, improved positive mental health, and describing social and economic outcomes, such as increased education attainment and decreased costs from sick leave and crime.DataPrev will enter the programmes into a standardized online information system. DataPrev will support policy making, research and practice by translating the evidence into guidelines and training for informed decision making, understanding effective interventions, improving existing implementation, and providing the arguments and outcomes to invest in effective interventions across Europe. DataPrev will constitute a building block of an integrated set of European databases and will provide the evidence base to inform policy making at the European and country levels, including support to the implementation of the forthcoming EU Strategy on Mental Health.