Organic farming in Europe is governed by Regulation (EC) 834/2007 and standards of private label organisations. Whereas compliance with the production rules is inspected on a regular basis, there is no monitoring of the fulfilment of the organic principles, particularly the principle of health. The purpose of this study was to assess the level of production diseases in organic dairy herds across Europe. National milk records and animal movement data were retrieved and a selection of the lactating cows was scored for lameness according to the Welfare Quality® protocol on a sample of farms. Prevalence of production diseases were calculated using sets of herd-level indicators and common R scripts. In total, 192 farms participated, i.e. 60 in Germany, 23 in Spain, 54 in France, and 55 in Sweden. Herd size expressed as cow-years ranged from 7 to 377; smallest in Spain (median [m]=30) and largest in Sweden (m=68). In all countries Holstein was the predominant breed with shares of 100% in Spain, 53% in France, and 41% in Germany as well as Sweden. Median energy-corrected milk yield was 6,588 kg in Germany, 5,742 kg in Spain, 6,378 kg in France, and 8,979 kg in Sweden. Herd prevalence of subclinical mastitis, defined as composite milk samples above a somatic cell count of 100,000 cells/ml, had a range of 19-94%; lowest in Sweden (m=44%) and highest in Spain (m=58%). Across countries a median of 10% of animals were at risk of ketosis, diagnosed by a fat-to-protein ratio >1.5 during the first 100 days of lactation (range 0 – 45%). Milk fat percentage <3.0 after 30 days in milk was used as indicator for subacute ruminal acidosis (SARA). Herd prevalence ranged from 0 to 42% with an overall median of 3% and Spain deviating the most (m=15%). Prevalence of prolonged calving interval (>400 days) was highest in Spain (m=63%) and lowest in Germany (m=36%) with a range of 4-91%. Overall (moderate and severe) lameness prevalence ranged from 0 to 79% and was lowest in Sweden (m=4%) and highest in France (m=23%). It can be concluded that the level of production diseases varies widely between organic dairy farms in Europe with a considerable proportion of farms not meeting the aim of good animal health. The results call for new, improved strategies to achieve good animal health in organic dairy systems, starting with unified monitoring procedures. This project has received funding from the EU FP7 for research, technological development and demonstration under grant agreement n° 311824 (IMPRO)