Abstract. In term of maintenance, parts must be maintained to satisfy operating conditions. Although, maintenance is costly and unprofitable, it is indispensable. Thus, reducing maintenance costs without reducing maintenance is one of the critical issues. Since maintenance costs mainly come from resources, they should be properly managed to minimize the cost. Hence, the goal of this paper is to find the optimal number of resources for required maintenance activities. Two mixed-integer programming models are developed. The first model is used for a long-term plan to find a proper number of resources while the second one generates a maintenance schedule for a shorter time frame to verify feasibility of the plan.