ABSTRACT THE selection of irrigation systems and management of irrigation water to maximize profit from crop pro-duction implies an optimization process of some sort. Such an optimization of irrigation system design is a complicated task and most often it is done by intuition. It involves the physical system, crop growth patterns, crop response to water and fertility and on-farm manage-ment practices. This paper presents a methodology for relating the selection of irrigation system design parameters to the crop production profitability. Irrigation system unifor-mity along with the scheduling of applied water has an important effect on crop yield and thus net farm income. A computerized technique is used which related system uniformity and scheduling practices to crop growth and production. For a given irrigation system design, furrow, sprinkle, or trickle, and a particular scheduling scheme, the seasonal water application which will maximize the net profit from a specified crop can be estimated. The computerized mathemathical model requires data relating system costs and design parameters to water ap-plication uniformity, crop-water production functions (from field data or crop growth models), production costs, and system capital costs. This systematized design process allows the designer to evaluate relative trade-offs between water, system and crop production costs, and returns with relative ease. Without this capability many irrigation systems, as a result of minimal effort expended in their design, are less than adequate for the field condi-tions in which they must operate. The inclusion of more relevant variables into a workable design process should prove helpful in increasing the designers' awareness of the interaction of crop production with irrigation systems. It is not our purpose to present an exhaustive array of design examples. However, field based crop pro-duction and economic data for sugar cane are used to il-lustrate the technique.