Contralateral prophylactic mastectomy use has increased over the past decades among women with early-stage breast cancer. Racial differences in contralateral prophylactic mastectomy use are well described, but with unclear causes. This study examined contralateral prophylactic mastectomy use among black and white women and the contribution of differences in perceived risk to differences in use. We surveyed women diagnosed with early-stage unilateral breast cancer between ages 41-64 in Pennsylvania and Florida between 2007-2009 to collect data on breast cancer treatment, family history, education, income, insurance, and perceived risk. Clinical factors-age,stage at diagnosis, receptor status-were obtained from cancer registries. The relationships between patient factors and contralateral prophylactic mastectomy were assessed using logistic regression. The interaction between race and contralateral prophylactic mastectomy on the perceived risk of second breast cancers was tested using linear regression. Of 2182 study participants, 18% of whites underwent contralateral prophylactic mastectomy compared with 10% of blacks (p < 0.001). The racial difference remained after adjustment for clinical factors and family history (odds ratio = 2.32, 95% confidence interval 1.76-3.06, p < 0.001). The association between contralateral prophylactic mastectomy and a reduction in the perceived risk of second breast cancers was significantly smaller for blacks than whites. Blacks were less likely than whites to undergo contralateral prophylactic mastectomy even after adjustment for clinical factors. This racial difference in use may relate to the smaller impact of contralateral prophylactic mastectomy on the perceived risk of second breast cancers among blacks than among whites. Future research is needed to understand the overall impact of perceived risk on decisions about contralateral prophylactic mastectomy and how that may explain racial differences in use.