From a brief review of the right to healthcare won by the Brazilian citizens, this article aims to discuss Sistema Único de Saúde (SUS - National Health System) throughout its trajectory of 20 years, providing a critical review of the progress achieved in healthcare and the challenges to be overcome. It discusses the issues of: the right to healthcare as the State's responsibility based on the Alma-Ata Conference, the Federal Constitution and the Organic Laws on Health; SUS guidelines involving the competences of the Union, States and Municipalities. It also approaches the importance of the Family Health Strategy for the consolidation of Primary Care in Brazil, the difficulties in the process of regional health planning, and the role of management and social participation as the bases for the construction of the SUS we want.
National Health System; Public Health; National Health Policy