This thesis talks about the participation of the Catholic Institutions on the Social Assistance City Council/CMAS, understanding it as one of the fundamental spaces for determination and consolidation of the Unified System of Social Assistance/ SUAS and the National Politics of Social Assistance/ PNAS referring to the city of Rio de Janeiro during 2004-2008. On this new politics, the catholic institutions’ actions can be integrated to the social-assistance networks for rendering of services, as well as to the social control as agents of the politics itself. Certainly, this new status positions them as entities regulated by the State or, as it says on the politics, acting under one command of the State in their different locations. Our goal with this study is to analyze the new contract of public politics of Social Assistance and the role established by the catholic institutions, especially in relation to their actions in the compass of deliberative division, in other words, in the democratic realm of social control. The theoretical referential chosen verses about participative democracy, democratic public management and hegemony, social control and the history of the Catholic Church in Brazil. It was possible to learn about the social and historical context in which the Counsels was originated, the participative conditions of the Catholic Church in Rio de Janeiro. To develop this study, we used assembly documentation and internal regiments of the Social Assistance City Council in Rio de Janeiro. Besides, we participated on direct observation of 14 Council Sessions, among ordinary and extraordinary meetings between September 2008 and October 2009. The empirical universe of the research counted on 12 semi-structured interviews with counselors that integrate (and/or integrated) the CMAS. The results showed a type of democratization with innumerous boundaries in which the Civil Society has a hard time, having access and/or understanding the complexity of the governmental dynamics and the public management of the politics. As for the catholic institutions, the participation on the CMAS is legitimated by its long trajectory on the history of Social Assistance, beside a relatively high level of the professionalization of their representatives. Although the counselors are actors with a long participative experience, the majority of them recognize the limitation of the interventions on the social control. On a concrete level of the council, the catholic institutions act in a fragmented way and the hegemonic articulation is done by the local ecclesiastic power.