Use of simulation to analyze and plan maintenance activities is still limited compared to planning production activities. The paper discusses a simulation based approach to quantify the effects of maintenance decision making by identifying the related performance indicators. The aim of the paper is to quantify the production maintenance related decisions, in terms of Key Performance Indicators (KPIs) determined trough interwievs and simulation. The approach is exemplified in a manufacturing case-study. The results show that use of simulation tool has the potential to be a strategic decision support tool for production maintenance in the production system.