The 2nd target of the EU Biodiversity Strategy requires the member states to assess and map the most important ecosystem services (ES) and integrate these results into policy decisions. Led by the Ministry of Agriculture an EU-cofinanced project entitled „Strategic Investigations on the long-term preservation and development of natural heritage of Community Importance and on the implementation of the EU Biodiversity Strategy 2020 objective” has started in Hungary in 2016 to fulfil these goals. The project has four main elements, focusing on 1) species and sites of Community Importance, 2) mapping and assessment of ES (MAES-HU), 3) defining landscape character types and methodology development for their protection, 4) planning of green-infrastructure development. The MAES-HU aims to build up spatial databases of ecosystems and ES in Hungary, and assess them using biophysical, economic and social indicators. To ensure broad scale scientific, policy and social credibility, the project puts high emphasis on participatory planning and stakeholder involvement. Prioritization of ESs for assessment was implemented in a series of workshops according to the main ecosystem categories: forests, water bodies and marshy areas, grasslands and arable fields (in a joint workshop but with separate evaluation) and urban ecosystems. Experts from different fields (8-14 per workshop) were invited to prioritise and shortlist the ES from CICES 4.3 based on expert consensus on their perceived societal importance in Hungary. After careful evaluation of the process and its outcomes, the MAES-HU working group finally chose 13 ES to map and assess during the remaining three years of the project until the end of 2020. The methodology of the assessment is built on the guidelines of the EU MAES working group and technical reports of former national assessments of several EU member states. The evaluation of the prioritized ES will be conducted in a four step process along the four levels of the cascade model: 1) condition of ecosystems, 2) capacity (potential supply) of the ecosystems for the selected ES, 3) actual use of the selected ES, 4) contributions of ES to human wellbeing. The assessment will last for about two years and will be performed by six expert working groups, involving around 40 experts from different fields. Graphical representations (i.e. mapping) will take place at all cascade levels using a detailed ecosystem map. Economic evaluation of specific ES is also planned. In the last year of the project, planning of different future scenarios will take place based on the joint evaluation of the assessed ES. The results of the MAES-HU project will hopefully assist the sustainable management of environmental resources, the development the green-infrastructure network, improved communication between different sectors, to incorporate the results into biodiversity and sectoral policies, and to reach the UN Sustainable Development Goals.