Background: This study aimed to evaluate the association between complementary and alternative medicine (CAM) use and fear of cancer recurrence (FCR) among breast cancer survivors, using a validated multidimensional FCR-assessing instrument. Despite the debate over its medical effects, the use of CAM in breast cancer survivors is increasing. Methods: We recruited 326 breast cancer survivors who had completed the primary cancer treatment. Information on CAM use was obtained using a self-administered questionnaire, and FCR was assessed using the Korean version of the FCR Inventory (FCRI). Multivariate linear regression analysis was performed to evaluate the association between CAM use and FCR. Results: CAM users had higher total FCR scores than CAM non-users after covariate adjustment (CAM users: 74.6 vs. CAM non-users: 68.7; P=0.047). Among the FCRI subscales, CAM users showed higher coping strategy scores (CAM users: 22.3 vs. CAM non-users: 20.6; P=0.034) in the multivariable adjusted analysis. The use of multiple types of CAM was associated with increased FCR in a dose-dependent manner (P=0.002). Conclusion Breast cancer survivors who used CAM had a higher FCR than CAM non-users. The dose-response relationship between the use of multiple types of CAM and FCR suggests that breast cancer survivors who use multiple types of CAM should be provided with appropriate psychological interventions to decrease FCR.