A methodology is presented that permits simultaneous consideration of the economics of production and groundwater contamination hazard of pesticide use. An example is constructed for weed control in soybean (Glycine max) production at Clayton, North Carolina. A cost/groundwater hazard frontier is, developed that can be used to identify and illustrate the cost tradeoffs of selecting alternative weed control strategies that reduce the risk of adverse health effects from drinking contaminated groundwater. 1The methodology relies on models to estimate costs, crop yields, pest competition, and leaching.of pesticides; thus, its applicability depends on availability of local data and appropriately validated models for the site considered. The cost/groundwater hazard frontier provides an excellent decision aid to assist pesticide users in making cost-effective and environmentally favorable production decisions. I:t is also useful in evaluating policy or the value of new pest control technologies, as it indicates a farmer's ability to substitute alternatives for currently used practices.