This study was conducted to investigate how much total feed cost can be curtailed by the application of linear programming compared with the conventional hand calculating method in determining the feed formula in feed mill. Data were collected from a feed mill producing 19 different kinds of feed and having capacity of producing 5,000 tons of feed a month. According to the results of analysis, the least-cost feed formulation by linear programming showed a decrease of 4,793,172 won monthly in total feed cost as compared with the conventional hand calculating method. But, to confirm the results of this study, it is necessary to conduct further emperical studies.