This study examines elements representing the organizational principles contained in the theoretical and juridical framework of Brazil’s Unified Health System (SUS). It is a qualitative study conducted on the basis of the Theory of Social Representations using the technique of thematic content analysis applied to Laws 8080/90, 8142/90, NOB 91, NOB 93, NOB 96, NOAS 2001, NOAS 2002 and the 1988 Federal Constitution and Rio de Janeiro State Constitution. The results revealed 531 units of analysis, grouped in four categories: system decentralization, health system hierarchization, health services regionalization and social participation. Connecting and orienting the categories was the SUS principles as a representation organizing the health system, at the same time as the municipality emerged as an image-based dimension of the representation, around which all the principles organized. Decentralization figured prominently as content in the representation, while the documents, in their practical aspect, place particular importance on municipalization as one of the goals of the system. Funding appears only in the decentralization category, representing nearly half its content. The study concludes that these documents were drafted in a dynamics comprising movements seeking to organize the system, as well as to reconcile among representations present in society. It was particularly important to study the theoretical and juridical framework of the SUS on a Theory of Social Representations approach, which revealed the endeavor to construct a new representation of Brazil’s health system appropriate to the demands and expectations of various social groups in interaction.