Farmers and policy makers rely on crop management data to evaluate socio-economic and environmental sustainability of cropping practices. The use of pesticide-treated seed is a widely used practice worldwide to control seed- and soil-borne pathogens affecting crop establishment and yield. In Europe, farmers raise concern about risks of yield losses due to a lower or no availability of chemicals previously used for seed treatment due to tighter restrictions imposed by the EU pesticide regulation 1107/2009, including the ban of several widely used fungicides (e.g. thirams, Metalaxyl-M). Within this context, research needs to provide a clear answer as to whether the economic viability of arable farms will be jeopardized when there is no access to pesticide-treated seeds. To respond to this concern, a 6-year specific project has been set up within the framework of French national action plan Ecophyto aiming at assessing economic and environmental sustainability of cropping systems without pesticide seed treatment compared to commonly used pesticide-treated seed. Large-scale farmer-led experiments using sequences of key arable crops (wheat, barley, maize, oilseed rape etc.) were put in place across contrasted environmental conditions of NorthEast France. Preliminary results show no significant yield differences between pesticide-treated and non-treated seeds raising questions on the prophylactic use of pesticide-treated seeds to yield gains.