Abstract Background: Eyebrow and eyelash loss are widely recognized as consequences of some chemotherapies, but prevalence and predictors are understudied. The purpose of this study was to evaluate real world experiences of eyebrow and eyelash loss during treatment for breast cancer. Methods: Breast cancer survivors participating in the ongoing prospective Mayo Clinic Breast Disease Registry (MCBDR) were mailed a survey one year after diagnosis. Respondents were asked to recall their severity of eyebrow and eyelash loss since diagnosis, measured from “no loss” to “a little loss” to “a lot of loss” to “complete loss”. Results: 524 participants were mailed a survey including these questions between May 2020 and November 2020; the median time from diagnosis to survey completion was 12 months (range 6 months). Of the 265 participants whose responses were available for analysis (median age 60.8 years), 88 (33%) had received chemotherapy, including 39 (44%) who received doxorubicin and cyclophosphamide, 16 (18%) who received docetaxel and cyclophosphamide, 56 (64%) who received paclitaxel, and 11 (13%) who received carboplatin. 173 (65%) had received endocrine therapy: 56 (32%) of patients who received endocrine therapy received tamoxifen, and 115 (66%) received aromatase inhibitors. 124 (47%) reported at least a little eyebrow loss, and 22 (8%) reported complete loss. Forty-seven percent reported at least a little eyelash loss, and 27 (10%) reported complete loss (Table 1). In the subgroup of 88 patients who received chemotherapy, the rates of at least a little eyebrow and eyelash loss were 50% and 55%, respectively, and rates of complete loss were 8% and 9%. Rates of eyebrow and eyelash loss did not appear to differ significantly by age. Conclusion: Eyebrow and eyelash loss are frequently reported during breast cancer-directed therapy. Future investigations into the incidence and treatment of this side effect are needed. Table 1.<55 years old55+ years oldEyebrow Loss (N)%Eyelash Loss (N)%Eyebrow Loss (N)%Eyelash Loss (N)%No Loss4551%4753%9655%9353%A Little Loss2629%2225%3922%3922%A lot of loss1011%1112%2715%2514%Complete Loss89%910%148%1810%Funding Source: Breast Cancer Research Foundation (CLL) Clinic Citation Format: Elizabeth Cathcart-Rake, Charles L Loprinzi, Fergus Couch, Janet Olson, Brittany Dulmage, Maryam Lustberg, Nicole Larson, Kathryn J Ruddy. Eyebrow/eyelash loss among survivors [abstract]. In: Proceedings of the 2021 San Antonio Breast Cancer Symposium; 2021 Dec 7-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2022;82(4 Suppl):Abstract nr P4-10-11.