Abstract Why did medical research involving human subjects, a practice that is arguably as old as medicine itself, come to be regulated by research ethics committees in the late twentieth century? In this essay, I answer this question for the Netherlands, by querying the rise of ethics review in the 1970s and 1980s through the lens of “institutional isomorphism”. Drawing on the classic work of Paul Dimaggio and Walter Powell, I argue that extra-national changes to funding and publishing requirements in this period were identifiably more important for the emergence of ethics review in the Netherlands than were ethical concerns for research misconduct – a process that was marked by definitive elements of internationally coercive, and perhaps also of mimetic isomorphism. In addition, I detail how, as a consequence of these developments, those involved in Dutch ethics review came to consider “variation and inconsistency” as one of the system’s biggest problems in the late 1980s. To remedy this, numerous normative isomorphic attempts were undertaken in the late twentieth century to make all Dutch research ethics committees act in the same way. This emphasis on institutional homogeneity has been borne out in the Netherlands, even though it has repeatedly been criticized for hampering democratic and ethical decision-making.