Abstract Background: Patients with breast cancer face many health issues during the cancer care continuum. Chemotherapy and radiotherapy can cause hearing and balance problems, e.g., tinnitus, hearing loss, and vertigo or persistent dizziness, negatively affecting patients’ health outcomes and quality of life. Hearing loss is more prevalent among cancer survivors than in the general population. However, little attention has been paid to tinnitus, hearing loss, and vertigo specifically among breast cancer patients and survivors, and it is unclear whether these symptoms vary across racial/ethnic groups. Methods: Between July and September 2023, we surveyed patients enrolled in the Chicago Multiethnic Epidemiologic Breast Cancer Cohort about whether they experienced tinnitus, hearing loss, and/or vertigo. Racial/ethnic groups included Asian or Pacific Islander (API), Black, Hispanic, and White. To examine racial/ethnic differences in hearing and balance problems, we fit separate multivariable logistic regression models, controlling for sociodemographic and clinicopathologic factors. Adjusted odds ratios (AOR) and 95% CIs were calculated. Results: Of 1,462 patients, the mean age was 54.2 years (SD 11.4), with a median duration from diagnosis to survey of 8.2 years (IQR: 5.0-12.4). Most were White (69.8%), followed by Black (22.7%), API (3.8%), and Hispanic (3.7%); and 46.0% received chemotherapy. Overall, 15.1%, 13.6%, and 7.7% reported experiencing tinnitus, hearing loss, and vertigo, respectively. Similar prevalences of these symptoms were observed among survivors who had received chemotherapy. By race/ethnicity, 16.1% of Black patients reported experiencing tinnitus compared to 15.6% of White, 9.4% of Hispanic, and 3.8% of API patients (P=.050). White patients reported a higher proportion of hearing loss (15.5%) than Hispanic (14.8%), Black (8.0%), and API (7.8%) patients (P=.004). A higher percentage of Black patients (13.2%) reported experiencing vertigo than White (6.5%), Hispanic (5.7%), and API (1.9%) patients (P=.001). After adjusting for demographic and clinical characteristics, Black patients had lower odds of experiencing hearing loss than White patients (AOR 0.39, 95% CI: 0.20-0.75). Compared with White patients, Black patients had greater odds of experiencing vertigo (AOR 1.80, 95% CI: 1.01-3.21). Due to limited power, we did not observe statistically significant differences in vertigo or hearing loss between API or Hispanic survivors and White survivors and in tinnitus across racial/ethnic groups. Older age and longer duration from diagnosis to survey were associated with greater odds of tinnitus or hearing loss. Conclusions: In this multiethnic cohort, hearing and balance problems were prevalent and varied by race/ethnicity among breast cancer patients. Our findings suggest that oncology programs should consider routine screening for these symptoms, encourage patient-provider discussion to identify unmet needs, and address racial/ethnic disparities to improve hearing and balance-related quality of life of breast cancer survivors. Citation Format: Jincong Q. Freeman, Fangyuan Zhao, Wenji Guo, Rita Nanda, Olufunmilayo I. Olopade, Jayant M. Pinto, Megan J. Huisingh-Scheetz, Dezheng Huo. Prevalence of and racial/ethnic differences in hearing and balance problems in a multiethnic cohort of patients with breast cancer [abstract]. In: Proceedings of the 17th AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2024 Sep 21-24; Los Angeles, CA. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2024;33(9 Suppl):Abstract nr C036.