Climate change may affect the use of pesticides and their associated environmental and human health impacts. This study employs and modifies a partial equilibrium model of the US agricultural sector to examine the effects of alternative regulations of the pesticide and greenhouse gas emission externality. Simulation results indicate that without pesticide externality regulations and low greenhouse gas emission mitigation strategy, climate change benefits from increased agricultural production in the US are more than offset by increased environmental costs. Although the combined regulation of pesticide and greenhouse gas emission externalities increases farmers' production costs, their net income effects are positive because of price adjustments and associated welfare shifts from consumers to producers. The results also show heterogeneous impacts on preferred pest management intensities across major crops. While pesticide externality regulations lead to substantial increases in total water use, climate policies induce the opposite effect.