The traditional production of billet continuous casting process results in production loss due to operator's decision made on the length of cuts of the last billets in each strand. This paper presents an application of linear programming for minimizing remnant in billet casting process at Siam Iron and Steel Company. The mathematical model using zero-one variables is formulated to minimize the remnant in cutting the last billets in each strand and obtain the maximum number of billets at the specified length. The model has been programmed using LINGO software. The computer communication system has made it possible to automatically use the decision variables obtained from the computation to achieve the maximum number of good billets with minimum remnant. The result of the implementation shows that the maximum number of good billets can be achieved with zero remnant. Compared to the conventional production system, this increases in yield as much as 5.344 tons/month/line. And finally the computer program can work successfully in real time. [PUBLICATION ABSTRACT]