The main objective of this research is to determine whether the change of control mechanisms in a public organization contributes to enhance the performance on its core activity. It is a case study focusing on the change occurred in the end of 1999 in the supervision area of Banco Central do Brasil (the Brazilian Central Bank), after this organization had received the newly created task of prevention and combat moneylaundering in the financial system. The understanding of the determinants and modes of change, the components and forms of organizational control and the different perspectives to performance build up the theoretical background of this work. Secondary data - essential to establish the research variables - were mainly gathered from database, publications and internal documents from Banco Central do Brasil. Obtained results point out a significant flexibilization of the focused organization. However, the performance indicators selected to this research do not have equally favorable outcomes. These results, compared to the change implementation process, suggest the influence of a set of factors not considered in this process, such as personnel adequacy and work process legitimacy.