The article analyzes how the process of the professionalization of physicians in São Paulo related to healthcare policy under the administration of São Paulo governor Adhemar de Barros (1947-1951) during a period of broad change in the realm of health known by São Paulo physicians as the "socialization of medicine." Medical professionalism confronted certain ambivalences under this populist administration, including doctors' struggle to achieve pay equal to that of state public attorneys; the establishment of a state health department; and some contradictory ties between the area of health under Adhemar and the professional ideology and organization of medicine in São Paulo. The article undertakes a more in-depth analysis of the ideological manifestations of important leaders in the state's medical community.