GEMAS (Geochemical Mapping of Agricultural and Grazing Land Soil in Europe) is a cooperative project between the Geochemistry Expert Group of EuroGeoSurveys and Eurometeaux. In total, more than 60 international organisations and institutions worldwide were involved in the implementation of the project. During 2008 and 2009, a total of 2219 samples of agricultural (arable land soils, 0 – 20 cm, Ap samples) and 2127 samples of grazing land (pasture land soils, 0 – 10 cm, Gr samples) soil were collected at a density of 1 site/2 500 km² each from 33 European countries, covering an area of 5,600,000 km². All samples were analysed for 52 chemical elements after an aqua regia extraction, 41 by XRF (total), TC and TOC. In the agricultural soil samples, 57 elements in a mobile metal ion (MMI®) extraction and Pb isotopes ratios were also analysed. In addition to the chemical element contents, soil properties and soil parameters such as pH, particle size distribution, effective cation exchange capacity (CEC), MIR spectra and magnetic susceptibility were investigated and some coefficients were calculated. All analytical results were subject to tight external quality control procedures. The GEMAS project thus provides for the first time fully harmonised data for element concentrations and bioavailability of the elements at the continental (European) scale. The geochemical maps provided in the data series “GEMAS - Single element maps” and “GEMAS - Parameters and indices” show an unbiased representation of the distribution patterns of the investigated elements and parameters. The data series “GEMAS - Supporting information” provides additional information to support the interpretation of these geochemical maps. The data set “Annual precipitation” belonging to this data series provides maps of the annual precipitation in the project survey area in the years 1960-1990 and 1970-2000 (data sources: UCDAVIS, worldclim.org).