Patients in Quebec can legally obtain medical assistance in dying (MAID) if they are able to give informed consent, have a serious and incurable illness, are at the end of their lives and are in a situation of unbearable suffering. Since the Supreme Court of Canada’s 2015 Carter decision, access to MAID, under certain conditions, has become a constitutional right. Quebec physicians are now likely to receive requests for MAID from their patients. The Quebec and Canadian laws recognize a physician’s right to conscientious objection, but this right is contested both in the medical ethics literature and in the public sphere. This paper presents the results of a qualitative study conducted with twenty Quebec physicians who did not integrate MAID into their medical practice, either because they were opposed to or deeply ambivalent about MAID. The interviews aimed to explore the reasons – religious and secular – for opposition to or ambivalence towards MAID. The secular reasons given by participants were grouped into four main categories: 1) the ends of medicine and professional identity, 2) the philosophy of palliative medicine and resource allocation in palliative care, 3) benevolent paternalism, the “good death”, and the interests of future selves, 4) the risk of a slippery slope and the protection of vulnerable people.