Research ethics commissions (REC) concentrate a large part of the debates on research ethics. However, few ethnographic inquires have been carried out to investigate their work. By developing a pragmatic approach to REC, this article seeks to reconsider how to approach this debate by thinking of research ethics as a process in the making. This article is based on an ethnographic study conducted at the REC of a Swiss canton. Firstly, it focuses on the work modalities of the REC, which functions as a collective agency that evaluates submitted research projects. Secondly, the article aims to characterize the work of the REC. To produce robust decisions, the REC articulates a plurality of conventional foundations that are sometimes in friction. In conclusion, we reassess the contributions of a pragmatic approach to capture and understand the production of research ethics, but also to discuss its modalities.