This work presents the change process of Telebahia S/A, a public organization part of the previously Brazil state-owned monopoly company of telecommunications,Telebrás S/A, in a context of changes in this specific sector based mainly on privatization. Telebahia S/A, as well as all Telebrás System, was privatized in July 1998, integrating at that time Tele Norte Leste Participações S/A. The present article analyzes the changes occurred in the organizational social structure - meaning the relationships between the parts of the organized whole (Hatch,1997). To illustrate this process of structural change, Greiner"s Life CycleTheory (1972) and Mintzberg"s typology (1995) - ideal types- were complementarily used, identifying the trajectory of the enterprise and its respective designs through the time. The case study demonstrated that the organization has passed through a series of transformations before the privatization that made it to look like a hybrid model of organization, more decentralized and empowered. The study presents the hypothesis that the privatization would reinforce this process, in a way of a general flexibleness in Telebahia S/A. Nevertheless, the empirical evidences show a centralizing process in the matrix.