Abstract Inspection and maintenance of rotating equipment have gained credit in petrochemicals, refineries and oil and gas industries over the past decades due to the hazard failures resulting from overpressures and fluctuated temperatures surrounding the industrial zone. Therefore, any equipment operating under the harsh operational conditions should take the cost and time of inspection and maintenance into account. Maintenance of rotating equipment is an expensive event in terms of the cost and time, which are the driving forces to improve the maintenance performance. The paper aimed at optimizing the maintenance schedule for the grouped pumps in the refinery plant using the expected cost criterion and expected cost-variance criterion. This is characterized by the application of techniques to prolong equipment life, minimize downtimes, and enhance all aspects of reliability, availability and maintainability. The results showed that the cost and time of maintenance could optimize based on the rotating equipment, which could implement according to the preventive and corrective maintenance policy. The results analysis has revealed that applying optimization of maintenance schedule could help practitioners in decision-making to estimate the optimal cost and time, and reduce planning efforts in the future............................. Keywords:........... Pumps equipment, Maintenance policy, Cost and time of maintenance.