The paper presents a Decision Support System (DSS) for the production planning of Agricultural pesticide. The unique features of pesticide production are identified and the resulting planning trade-off's are explained. The DSS consists of six loosely coupled modules. A mathematical programming model forms the basis of the DSS, whose objective is to minimize the total cost of production. The model is also designed to capture seasonal demand fluctuations, variations in labor cost, source, cost and availability of raw material and plant operating mode. The DSS is illustrated by planning the manufacturing of nine products on two production lines to satisfy demand over eighteen months. The system has been in use for pesticide production planning in a major US plant for more than five years. Such use helped in rationalizing production planning decisions and led to tangible savings in production and inventory cost, over the duration of its use.