There are studied on the evaluation of flexibility and design/operation of FMS. However. a new method that can assess the performance of FMS is propose in this study. To evalute the performance of an FMS the ordinary for total cost is not applied. Instead, a specially developed cost function is used to measure the performanced of proposed systems. The procedure is developed for deterministic variables cases. An FMS can produce various products systematically under computer control the evaluation of an FMS operation is not a simple task. The proposed procedure is done through computer simulation due to the complicated nature of the problem. A simulation model is developed using SIMAN and FORTRAN for practical application.