Popowich B, et al. - Recommendations in 10 guidelines regarding breast reconstruction after prophylactic and therapeutic mastectomy, recognized through a systematic search of websites and databases of reputable oncology guideline developers, were investigated for differences. Using the AGREE II tool, three reviewers performed the quality assessment of the guidelines, focusing on breast reconstruction specific documents rather than the general breast cancer guidelines. Alberta Health Services, Cancer Care Ontario, the American Society of Plastic Surgeons, and the Association of Breast Surgery/British Association of Plastic Reconstructive and Aesthetic Surgeons published the most comprehensive guidelines. For all four guidelines, AGREE II scores in the domains of “Scope and Purpose” and “Clarity and Presentation” were ranked relatively high while in the domains of “Applicability” and “Editorial Independence” the scores were ranked relatively low. The overall highest ranked guidelines were the Alberta and Ontario guidelines across all domains. These guidelines render consistent recommendations on who should obtain breast reconstruction education, who is a candidate for postmastectomy breast reconstruction, and the suitable timing of reconstruction and extent of mastectomy.