ABSTRACT
This paper discusses the historical construction of the Expanded Family Health Center (NASF, in Portuguese), based on the analysis of 17 documents edited by the Ministry of Health (MH) between 2005 and 2021. This is a qualitative study of documental review that seeks to understand how the regulations and official instructive ma-nuals have been shaping the way NASF teams operate. It proposes to divide the NASF construction process into five periods: previous move-ments (2003 to 2007);support guidelines (2008 to 2011);the universalization of nasf (2012 to 2015);expansion of support (2016 to 2018);and the dismantling of NASF? (2019 to 2021). The results show changes in guidelines over the years of the team’s existence, especially in relation to the matrix support concept and its two dimensions: technical-pedagogical and clinical care. This study also demonstrates the effects of the Previne Brasil Program on the NASF, which resulted in the reduction of 379 teams in 2020 and 2021. Ad-ded to this scenario is the SARS-CoV-2 pandemic, which may be repositioning NASF interventions in the Brazilian Unified Health System (SUS, in Portuguese).