Soil organic carbon (SOC) stocks in different terrestrial ecosystems have already been calculated. However, SOC stocks of grassy verges and grass-covered urban areas have never been reported. In this study the total grass-covered area of verges and urban areas in different agro-pedological regions of Flanders, Belgium was calculated and SOC stocks estimated. The total grassy area of verges along roads, waterways and railways was calculated to be 18 027 ha, 9530 ha for gardens and parks and 2360 ha for recreations areas. Total SOC stock for grass-covered verges, extrapolated to a depth of 1 m, was estimated to be 3520 kt SOC. Total SOC stock for grassy vegetation in urban areas was 1738 kt SOC. These total SOC stocks equate, respectively, to 0·10 and 0·05 of the total SOC stock in Flemish grassland.