Objective: this study analyzes the federalist decentralization materialized by decisions of the Brazilian Supreme Federal Court rendered during the SARS-CoV-2 virus pandemic. In this context, the aim is to consider the possibility of tacitly including municipalities within the concurrent legislative competence in the area of health, based on the elements of popularization and urgency. Methods: the study is based on bibliographic research – legal and public health doctrine – and legislative research, as well as ex post facto research, analyzing the causes and effects of Direct Action of Unconstitutionality 6.341, Allegation of Violation of Fundamental Precept 672, and Original Civil Action 3.451, all grounded in cooperative federalism. Results: as a result, the recognition of the municipality's duty to legislate in defense of health, especially in the inertia of other entities and limited only by regulatory agencies, and the existence of a delaying clash between legislative incompetence, urgency and popularization of the health system. Conclusion: it was concluded that the municipality was tacitly included in the legislative competence in the area of health by the decisions of the STF. Submission: 01/23/24| Review: 08/16/24| Approval: 08/16/24