Scholars believe that mass partisanship in Brazil is comparatively weak. Using evidence from a 2002 national survey, however, this study finds that the aggregate level of party identification actually falls only slightly below the world average and exceeds levels found in many newer democracies. Yet this finding is misleading, because the distribution of partisanship is skewed toward only one party, the PT. This trend results from a combination of party organization and recruitment efforts and individual motivation to acquire knowledge and become involved in politicized social networks. Partisanship for other parties, however, derives substantially from personalistic attachments to party leaders. This finding has implications for current debates about the status of parties in Brazil. Also important is the impact of the 2005 corruption scandal implicating the PT and President Lula da Silva's administration.