In recent years, Brazil has been highly revered for its response to HIV/AIDS. Despite the government’s delayed response, why and how did the national AIDS program eventually become so successful? This is even further puzzling when one considers the challenges associated with Brazil’s decentralized response to healthcare needs, lack of subnational resources and political will to effectively implement AIDS policy. This article maintains that Brazil’s successful response eventually required the strategic centralization of national AIDS bureaucratic and policy authority, entailing policies designed to aid local governments while creating fiscal policies incentivizing sub-national compliance with the national bureaucracy and more effective policy implementation. Taking advantage of renewed political support, kindled by international pressures and the president’s reputation-building pursuits, the sources of AIDS officials’ success, however, resided not in their technical and financial prowess, but in their ability to forge historically-based partnerships with civic AIDS NGOs and social movements sharing like-minded ideational beliefs in policy centralization. This article also discusses how these findings contribute new insights into theories addressing the reasons for centralization, as well as the ideational sources of gradual institutional change.