The problem of how to upgrade translucent optical networks is studied in this paper. This study is motivated by the cost advantage of not having network nodes fully equipped with transceivers in the beginning of network deployment but adding transceivers as and when it is necessary. A novel heuristic algorithm for the selection of nodes to upgrade (by adding transceivers) based on the transitional weight of the nodes and the length of the links is proposed. Spare transceivers in the nodes can be used to regenerate signals. An algorithm for locating the regeneration nodes in the network is also proposed. The proposed upgrade node selection algorithm is studied with the regeneration node selection algorithm and a wavelength weighted routing algorithm by means of numerical simulations. Simulation results show that upgrading translucent optical network by means of the proposed upgrade node selection algorithm has lower blocking probability and cost advantage compared to other strategies.