This paper focuses on intersections of medical ethics and religious commitments by charting conceptions of the Catholic doctor in French and English‐language normative texts from the mid‐nineteenth to the mid‐twentieth century. Behavioural norms for doctors were increasingly emphasised in writings on pastoral medicine, especially regarding obstetrics and advice on sexual hygiene, with the Ten Commandments and the Sacraments forming the initial ethical framework. From the 1890s, Catholic medical deontology emerged as a genre in its own right, reflecting a distinct identity of Catholic doctors in medical faculties and in their own professional societies. Simultaneously, the range of topics broadened. While traditional issues of reproductive ethics such as medical abortion and emergency baptism remained central concerns, eugenic sterilisation and euthanasia posed new challenges. Catholic doctors were now expected to take on a social role that went beyond the care of their individual patients, especially in questions of population politics. A popular contributor to the eugenics debate was the French medical scientist Alexis Carrel.