Abstract Background Adjuvant endocrine therapy (AET) is effective at reducing breast cancer recurrence risk. It is associated with adverse symptoms, including sexual symptoms (e.g., vaginal dryness, reduced libido, dyspareunia), that can contribute to medication nonadherence and poor quality of life (QoL). Black women are least likely to start and maintain AET. We conducted post hoc analysis of a randomized clinical trial (RCT) to examine racial differences in how sexual symptoms affect sexual satisfaction and how these contribute to differences in AET adherence for Black and White women with early-stage breast cancer. Methods We used data from a nonblinded RCT of women diagnosed with early-stage (Stage I-III), hormone receptor-positive breast cancer and prescribed AET at a regional cancer center in the U.S. Mid-South. We restricted to Black and White participants who completed surveys at enrollment, 6-, and 12-months (N=275). The Functional Assessment of Cancer Therapy-Endocrine Subscale (FACT-ES) captured sexual symptoms (e.g., vaginal itchiness, bleeding, dryness, discharge, change in interest in sex, and pain with intercourse) and PROMIS Sexual Function and Satisfaction captured changes in sexual satisfaction with 5-item options ranging from “not at all” to “very much.” The 12-item Short Form Health Survey measured QoL with physical and mental health component summaries (higher scores indicated better QoL). AET adherence, captured by an electronically monitored pillbox, was measured as the proportion of days participants took their medication as prescribed over the 1-year follow-up. We conducted race-stratified linear regressions to examine associations of sexual symptoms with QoL and adherence. Results Among 275 participants, 102 (37%) were Black. Black women reported greater severity of vaginal discharge and that loss of sexual satisfaction was due to sexual symptoms at 6- and 12-months (p<0.05). Vaginal itchiness, vaginal discharge, painful intercourse, and loss of interest in sex were associated with lower mental QoL for Black and White women at all three time points. However, loss of interest in sex was associated with lower physical QoL at all three time points for Black women only. Worsening vaginal dryness was associated with lower 6-month AET adherence for Black (p=0.018) but not for White women (p=0.90). Similarly, lower sexual interest and lower sexual satisfaction was associated with lower 12-month AET adherence for Black women (p<0.05) but not for White (p=0.21 and p=0.13, respectively). Conclusion Women with early-stage breast cancer on AET reported adverse sexual symptoms with associated reductions in their sexual satisfaction and physical and mental QoL. Vaginal dryness, reduced libido, and lowered sexual satisfaction are associated with AET nonadherence among Black women, a group with known adherence barriers and recurrence risks. Our findings suggest that adverse sexual symptoms and sexual health challenges contribute to racial disparities in AET adherence and QoL. Oncosexuality care interventions for Black women are needed. Citation Format: Janeane N. Anderson, Freddie Yang, Xin Hu, Gregory A. Vidal, Ilana Graetz. Racial differences in adverse sexual symptoms and implications for quality of life and adjuvant endocrine therapy adherence among women with early-stage 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 C053.