Background Preoperative breast magnetic resonance imaging (mri) is commonly requested by surgeons in the initial workup of women with breast cancer; however, its use is controversial. We performed a survey of breast cancer surgeons across Canada to investigate current knowledge about, attitudes to, and self-reported use of preoperative breast mri in a publicly funded health care system in light of the limited evidence to support it.Methods All identified general surgeons in Canada were mailed a survey instrument designed to probe current practice and knowledge of published trials.Results Of 403 responding surgeons, 233 (58%) indicated that they performed breast cancer surgery. Of those 233, 218 (94%) had access to breast mri and completed the entire survey. Overall, 54.6% of responding surgeons felt that breast mri was useful in surgical planning, and more than half (58.3%) indicated that their frequency of use was likely to increase over the next 5 years. Surgeons found preoperative mri most useful in detecting mammographically occult disease (71.5% of respondents) and in planning for breast-conserving surgery (57.3%). The main limitations reported were timely access to mri (51%) and false positives (36.7%). Responses suggest a knowledge gap in awareness of published trials in breast mri.Conclusions Our study found that, in early-stage breast cancer, self-reported use of mri by breast cancer surgeons in Canada varied widely. Reported indications did not align with published data, and significant gaps in self-reported knowledge of the data were evident. Our results would support the development and dissemination of guidelines to optimize use of mri.