Physician attitudes toward and lack of familiarity with guidelines have been identified as potential barriers to adherence in general, but little is known about their attitudes toward and use of cancer management guidelines specifically. This study surveyed 1500 surgeons and medical oncologists drawn from the AMA Masterfile in 2012. This report describes and compares the attitudes of medical oncologists and surgeons who treat patients with breast cancer regarding guidelines in general and the NCCN Clinical Practice Guidelines in Oncology (NCCN Guidelines) in particular, and their familiarity, use, and compliance with these guidelines. Of 896 respondents, responses were analyzed from the 766 who had seen at least one new patient with breast cancer in the past year. Mean participant age was 52 years; 25% worked in a teaching setting. Attitudes toward guidelines were generally favorable. Medical oncologists were more likely than surgeons to be aware that NCCN issues guidelines for cancer management (100% vs 74%; P<.001) and more likely to state that these guidelines generally influence their decisions (96% vs 70%; P<.001). Among those aware of NCCN Guidelines, 96% reported that they often agreed with NCCN recommendations, and 75% reported that almost all of their breast cancer treatment recommendations were consistent with these guidelines. Still, most providers (77%) also reported that they refer one-fourth or fewer of their patients with breast cancer to the NCCN Guidelines for Patients. Attitudes toward physician-directed cancer management guidelines are generally positive, and they are frequently used. However, existing guidelines seem to have greater visibility to the medical oncology audience than to surgeons, and patient versions are infrequently recommended.