Abstract How a profession is regulated and by whom are generally considered to be crucial questions. In Belgium, the most important regulator of the medical profession is the Order of Physicians. This institution is generally acknowledged to be a cornerstone of the Belgian profession's ‘overwhelming dominance’ and great autonomy. In this article, I will discuss the developments which led to the establishment of the Order of Physicians in 1938. One of the central themes is that in order to understand its establishment fully one has to take into account the ongoing struggle between profession, sickness funds and government as to the position of the profession within the planned obligatory health insurance system. It is likely that the typically Belgian involvement of interest groups and social movements in the political arena, in order to fight off political interference in issues considered to be private ones, facilitated the acceptance and the establishment of the Belgian Order of Physicians in 1938.