In a competitive electric market, high maintenance costs brought the necessity of process recruitment to increase the maintenance process efficiency and to extend the asset life time. Reliability centred maintenance has been continually improved together with proper asset management techniques to meet this necessity. This study presents an improved power transformer maintenance plan for reliability centred asset management of Turkish National Power Transmission System. At first, Markov model of existing maintenance procedure is constructed. Model solutions are used to compute the reliability indices and the total costs of the transformer. Then, sensitivity analysis was performed to determine effective transition rates of the model. Finally, optimal maintenance rates and corresponding reliability indices, total cost and life time were determined using actual service data and estimated transition rates. The results are compared with the existing maintenance plan.