Abstract Mitigating agricultural ammonia (NH 3 ) emissions in China is urgently needed to avoid further damage to human and ecosystem health. Effective and feasible mitigation strategies hinge on integrated knowledge of the mitigation potential of NH 3 emissions and the associated economic costs and societal benefits. Here we present a comprehensive analysis of marginal abatement costs and societal benefits for NH 3 mitigation in China. The technical mitigation potential of agricultural NH 3 emissions is 38–67% (4.0–7.1 Tg N) with implementation costs estimated at US$ 6–11 billion. These costs are much lower than estimates of the overall societal benefits at US$ 18–42 billion. Avoiding unnecessary fertilizer use and protein-rich animal feed could provide 30% of this mitigation potential without additional abatement costs or decreases in agricultural productivity. Optimizing human diets with less animal-derived products offers further potential for NH 3 reduction of 12% by 2050.