In this essay we examine the coevolution and cross-fertilization of environmental and agricultural economics over the past century. We discuss the key role that agricultural economists have played in the intellectual development of environmental economics. We focus on three primary contributions: incentive design, nonmarket valuation, and joint determination. The nature of these contributions is illustrated using specific examples from the literature. Agricultural economists' tendency to focus on applied problems has enriched and broadened both the academic debates and the policy advice provided by economists. Copyright 2010, Oxford University Press.