This paper discusses recently proposed methodology for the design of an optimum maintenance management program. The methodology is based on integrating a reliability approach and a risk assessment strategy to obtain an optimum maintenance schedule. The method is called risk-based maintenance (RBM). First, the likely equipment failure scenarios are formulated. Out of the many likely failure scenarios, the ones that are most credible are subjected to a detailed study. Detailed consequence analysis is done for the selected scenarios. Subsequently, a fault tree analysis is performed to determine the probability of failure. Finally, risk is computed by combining the consequence analysis and the probability analysis results. The calculated risk is compared against known acceptable criteria. The frequency of maintenance tasks is obtained by minimizing the estimated risk. The proposed methodology is used to answer two questions: Which equipment should be included in a scheduled maintenance program? When should the maintenance be scheduled? Offshore oil and gas process facilities involve hazardous chemicals (highly flammable and toxic) at extreme conditions of temperature and pressure. Proper maintenance of process equipment is one of the important activities to ensure safe and continuous operation of the facility. RBM methodology has been used to develop a detailed maintenance plan for safe and fault free operation of the facility. (C) 2004 American Institute of Chemical Engineers Process.