Results of a six-year study (1983-88) of on-farm center-pivot irrigation are being reported and published at various meetings nationally, regionally and locally. Information in this paper includes yield response of cotton to supplemental water applied by center-pivot irrigation systems in the Mississippi Delta. Irrigated and non-irrigated plots were paired using soil pH and cation exchange capacity (CEC) values to determine yield response. Field diaries, kept by cooperating producers, were utilized to obtain costs of production. A breakeven analysis, based on costs of production and selected product prices was used to evaluate the estimated yield response. Estimates of costs and returns were made to evaluate the production of non-irrigated cotton and irrigated cotton using center-pivot irrigation systems.