Manufacturing Execution System (MES) is a system that companies can use to measure and control critical production activities. This paper shows case study of implementation of MES (Manufacturing Execution System) and its methodology in a medium sized production company. This study focused on two important things in MES implementation. First, it provides critical success factors (CSFs) and construction method for success of MES implementation. Second, it presents guidelines for MES implementation in small and medium-size company. Some of the benefits with regards to MES implementation and its results are introduced in the end of this paper.