A European Union (EU-27) wide N2O emission estimate for the agricultural sector is presented, using the INTEGRATOR model, combined with detailed GIS-based environmental data and farming data. INTEGRATOR links various modules, calculating NH3, NOx, N2O, CO2, and CH4 emissions from housing and manure storage systems, agricultural and non-agricultural soils and surface waters, while accounting for the interaction between agricultural and non-agricultural systems through an emission-deposition model for NH3 and NOx. This study is limited to N2O emissions from housing and manure storage systems and agricultural soils. All emissions are based on N2O emission factors which depend on environment (weather and soil conditions), land use (grassland, arable land, crop residues), and management (type of manure and fertilizer, etc). We assessed the plausibility by a comparison of calculated present nitrous oxide emissions at country level with those derived by more simple emission factor approaches and detailed ecosystem models. The model was used to assess the impact of various farming practice packages to mitigate N2O emissions. For the agricultural sector of the EU-27, a total N2O emission of 347 kton N2O-N is calculated for the year 2000, which is comparable to other estimates. The overall achievable reduction in N2O emissions with the evaluated mitigation measures is about 25%. For the EU-27, the most effective measures are balanced fertilization and maximum manure application, but this is highly variable per country.