Objective: to reflect on the (in)visibility of the normative-legal apparatus on the workforce sizing in Brazilian nursing. Method: a theoretical-reflective essay was conducted by researchers who are part of the Brazilian Network of Studies and Research on Healrh Workforce Sizing and Planning. Past and current resolutions (product of a revocation) of the Federal Nursing Council on the subject, related studies and interpretative inferences guided the reflection. Results: the reflective positioning was based on two axes: Nursing workforce sizing: looking to the past to understand the present; and Normative and legal obstacles to nursing sizing. Conclusion: Brazil is a pioneer in proposing and updating technical and scientific standards that recommend methodologies and criteria for sizing the nursing workforce. On the other hand, the lack of a legal framework on the subject, linked to a plurality of “regulations”, shows that, in practice, staff sizing is commonly neglected. The revocation of Resolution number 543/2017 of the Federal Nursing Council, based on legalistic premises, reveals this reality. Advances of a political and, consequently, legal nature are required.