The Dutch Ministry of Agriculture (LNV) is investigating whether its regulatory framework around nutrients and greenhouse gases from agriculture, and especially livestock farming, could and should be structurally changed from a means-based approach to a goal-based approach. That is: instead of the current system of prescribing the exact measures to be taken by farmers to comply with environmental regulations, farmers might be held accountable for their actual performance (f.i. in terms of emissions and losses). This might provide farmers with more entrepreneurial and managerial freedom to steer their farm, while the policy goals would still be attained. This would mean a fundamental change in the system of these regulations, for which important questions would have to be answered about effectiveness, enforceability and legal tenability. In this context, the Ministry of LNV has asked WUR to explore the options and limitations for an Accountable Mass Balance (AMB) focusing on manure, nitrogen and climate, based on current monitoring tools. The goal of the reported project is to explore the options for developing an AMB using available data from the Annual Nutrient Cycling Assessment tool (ANCA). This kind of AMB would monitor and evaluate farmers’ performances, be the basis for individual accounting, incentivise or de-incentivise certain actions and be robust enough for use in legal procedures. The exploration has been carried out in close cooperation between researchers and policy workers.