Abstract. Due to reduction in petroleum production and aging production facilities, the Norwegian oil and gas industry is interested in optimization maintenance strategies and reducing costs. Currently the maintenance strategies are based on predetermined periodic (calendar or use time) preventive maintenance strategies that are developed based on statistical data and/or recommendation from the manufacturers. One possibility currently being explored is to use condition monitoring data available in the process monitoring system, to update and improve the predetermined periodic preventive maintenance strategies. Furthermore, we discuss some issues and challenges of the integration of available condition monitoring data in the planning and optimization of predetermined preventive maintenance strategies.