The Casa Fonte Colombo (CFC) is a religious organisation that assists people living with HIV/AIDS (PLWHA). The funding for its activities comes from public sources such as the Brazilian National STD/AIDS Program as well as the Catholic Church. Capuchin (Franciscan) priests run the CFC and it has an extensive group of volunteers made up mostly of women. Between 2006 and 2009, we observed daily life at the CFC and interviewed priests, volunteers, employees, service providers, and clients. We also attended meetings, group sessions, and celebrations. Everyday actions carried out by the CFC reveal the efforts to resolve the tension between the position of the Catholic Church and the Brazilian state in the politics of AIDS. These efforts affirm that the CFC presents itself as a space where the position of the Catholic Church, as much as the politics of public health, are re-worked, giving way to a progressive act of Catholic prevention and assistance for AIDS that we call 'theology of prevention'.