Introduction: The rate of contralateral prophylactic mastectomy (CPM) has recently increased. The aim of this study is to assess perceptions of contralateral breast cancer (CBC) risk among breast cancer patients and to evaluate tumor and patient factors associated with risk perception. Methods: We conducted a prospective survey study to evaluate perceptions of CBC risk in women newly diagnosed with ductal carcinoma in situ (DCIS) or stage I/II invasive breast cancer. Surveys were distributed in clinic prior to surgical consultation. Exclusion criteria included history of breast cancer, bilateral breast cancer, neoadjuvant chemotherapy or radiation for the current breast cancer, or BRCA mutation. Survey questions used open-ended responses or five-point Likert scale scoring (5 = very likely, 1 = not at all likely). Results: Seventy-four women (mean age 54.5 years) completed the survey. Diagnoses included invasive ductal cancer (66.2%), invasive lobular cancer (9.5%), and DCIS (20.3%). Most women (54.1%) underwent breast-conserving surgery; the remaining had bilateral mastectomy including CPM (17.6%) or unilateral mastectomy (10.8%). Overall, women substantially overestimated their risk of developing CBC. The mean estimated 10-year risk of CBC was 31.4% [95% confidence interval (CI) 24.7-37.9%] and 2.6 ± 0.15 on the rank scale. The perceived risk of CBC was not significantly associated with cancer stage, family history, age, or CPM. Conclusions: At time of surgical evaluation, women with unilateral breast cancer substantially overestimated their risk of CBC; however, this elevated risk perception was not associated with choosing CPM. Early physician counseling is needed to provide women with accurate information regarding their true CBC risk.