Physician recommendation for contralateral prophylactic mastectomy (CPM) has been shown to influence whether a patient chooses CPM. Few studies have explored physician knowledge about contralateral breast cancer (CBC) and local recurrence (LR) risk and whether knowledge is associated with recommendation for CPM. We conducted a cross-sectional survey of physicians at National Accreditation Program for Breast Centers-accredited breast centers across the USA. Physician knowledge levels of CBC and LR were assessed and correlated with recommendations for CPM. A total of 2412 physicians were surveyed with a 51% response rate (n = 1226). The results showed that 66% had correct knowledge about CBC risk and 57% had correct knowledge about LR. Moreover, 634 had high knowledge, viz. 176 (55.4%) breast surgeons, 171 (58.0%) medical oncologists, 196 (62.0%) radiation oncologists, and 72 (29.9%) plastic surgeons (p < 0.01). Compared with high knowledge, low knowledge was associated with favoring insurance coverage for patients at average CBC risk (53.8% vs. 39.8%, p < 0.01). Low knowledge was also associated with feeling that CPM was indicated in patients with high recurrence anxiety (39.2% vs. 28.9%), young patients with estrogen receptor (ER)-negative cancer (25.3% vs. 18.5%), and patients with two first-degree relatives with breast cancer (40.0% vs. 32.3%) (all p < 0.01). Multivariable analysis found physician type [odds ratio (OR) 3.76 for surgeons] and low knowledge (OR 1.46) to be significant independent predictors of favoring insurance coverage for CPM in patients at average risk. Physician knowledge about CBC and LR could be improved. Lower knowledge is associated with favorable physician recommendations for CPM. It is not clear whether improving physician knowledge will change recommendations for CPM.