- OBJECTIVES: To elicit Quebec physicians' attitudes towards extending medical aid in dying (MAiD) to incompetent patients and to compare the attitudes of family physicians to those of other medical specialists. METHODS: We conducted a postal survey among physicians caring for patients with dementia. We used hypothetical vignettes to elicit their attitudes towards MAiD and continuous deep sedation (CDS) to relieve suffering at end of life. Two patients were depicted in the vignettes: one with cancer eligible for MAiD and one with dementia. The generalized estimating equation approach was used to investigate factors associated with attitudes, including the stage of the illness (advanced vs terminal dementia) and the presence or absence of a prior written request. RESULTS: A total of 136 physicians out of 653 returned the questionnaire. Physicians favoured CDS over MAiD for relieving suffering in the cancer vignette (93% vs 79%; p = 0.002). In advanced dementia, 45% of physicians supported giving the patient access to MAiD with a written request and 14% without such request. At the terminal stage of dementia, these proportions increased to 71% and 43%, respectively (p < 0.001), reaching 79% and 52% among family physicians. Support for CDS in terminal dementia was lower than in end-stage cancer (68% vs 93%; p < 0.001) and equal to MAiD with a written request (68% vs 71%; p = 0.623). CONCLUSION: Many Quebec physicians support extending MAiD to incompetent patients with dementia to relieve suffering at the terminal stage. This finding will inform current deliberations as to whether MAiD should be extended to these patients.