In the present, simulation programs are very widespread tool in designing of new systems, improving the existing systems, etc. The simulation software is possible to apply in various sectors, e.g. production, logistics or the field of various services. This article is focused on the application of Witness – simulation software in the manufacturing process. The introduction of this article is focused on short description of simulation issue in the manufacturing processes. The last part of the introduction is focused on description of Witness simulation software. The material and method section describes the manufacturing process (material flow) from which the simulation model is created and subsequently optimized. The final part of this article provides overview of the results from suggested optimization.