In recent years, a vast amount of scientific literature has highlighted the benefits of nearby greenspace for physical and mental health, but the large variation in scope, methods and indicators used in these studies hampers the assessment of these benefits in the context of natural capital accounting. To our knowledge, this paper is one of the first studies to quantify and value these benefits in the context of natural capital accounting. A method was developed and applied to the Flemish region in Belgium for 2013 and 2016. The physical supply and use accounts for health are based on a set of selected dose-effect relations that quantify the impact of the availability of greenspace on 7 specific indicators for physical and mental health, including mortality, cardio-vascular diseases, diabetes and depression. The indicator for green-blue areas is the % of green-blue areas in total land use, calculated for 0.5, 1 and 3 km radius from the residence, based on detailed land-use maps (10m x 10m) for Flanders, Belgium. The base-line data for mortality and illness are average data for the Flemish region. These health impacts are weighted using Daly's (disability-adjusted life years) and aggregated. The total health benefits due to the availability of green-blue areas for the total Flemish population was estimated almost 85.000 DALY’s. This is 27% of the estimated total burden of disease in 2016 for the 7 selected diseases. The monetary accounts include assessments of avoided costs of illness (e.g. hospitalisation costs) and avoided absenteeism and productivity loss. In addition, we valued the years of life lost due to cardio vascular mortality based on simulated exchange values. The total monetary benefits amount to 464 Euro per inhabitant per year or 3 billion Euro per year for Flanders. This corresponds to 1.3% of the GDP, which reflects the importance of these benefits. Productivity gains and avoided costs of illness account for respectively 52 % and 36% of these costs. The methodology is incomplete as not all health ...