The gridded ammonia (NH3) emission inventory for Europe is updated using new emission factors for the emission from livestock and application of fertilizer. An inquiry was made to investigate the differences in agricultural practice between countries (Appendix 1). As only information on part of the factors which can influence the emission became available, country-specific emission factors could not be computed. Therefore the same emission factors were applied for every country. These were mainly based on emission factors derived from research in the Netherlands. The total gridded emission is about 7.6 Mtonne NH3 yr-1, which is 21% more than the emission survey of Buijsman et al. (1987) gives. This difference is mainly caused by application of different emission factors and for a minor part by differences in the number of animals. A detailed emission map for the Netherlands, Belgium and the western part of the FRG is presented, showing much higher maximum densities for these areas than the less detailed inventory for Europe does. The modelled average relative diurnal variation in the NH3 emission rate is about a factor 5. The average seasonal variation derived from measured concentrations in air and precipitation, corrected for meteorological variations, is about a factor 2. There does exist a descrepancy between the seasonal variation in the emission rate for the Netherlands derived from information on agricultural practice and from measured concentrations in air and precipitation for March.