Health education for socially marginalized populations challenges the efficacy of existing strategies and methods, and the pertinence of the educational and philosophical principles that underpin them. The Brazilian Community Health Agents Initiative (CHAI) hires residents of deprived marginalized communities to undertake health promotion and education in their communities. The ultimate goal of the CHAI is to connect populations with the public healthcare system by promoting social re-affiliation, protecting civil rights and enhancing equity of access to health services. In this article, we present the education work of community health agents through interplay between popular and scientific health knowledge in nine Rio de Janeiro shantytowns. A critical ethnographic research design, using thematic analysis, allowed us to explore agents’ education work to enhance family health literacy in shantytowns. Local culture and social practices inspire Agents to create original strategies to reconcile forms of health knowledge in their work.