Abstract Background: Evidence demonstrates inequities in receipt and persistence of hormone therapy among breast cancer patient populations based on race, ethnicity, insurance, and language. Institutions where patients seek cancer care may have an impact on receipt of treatment. It is unknown whether safety net hospitals, servicing a vulnerable patient population, exhibit inequities in receipt of hormone therapy for breast cancer. Study Design: We performed a retrospective study of patients diagnosed with all stages of hormone positive (ER+ and/or PR +) breast cancer treated at a safety net institution over the five year period from January 1, 2009 to December 31, 2013. The initiation of and persistence of hormone therapy were assessed by race, ethnicity, insurance status, and primary language. Persistence of therapy was defined as defined as at least 3 prescriptions (90 day supply) or more than 1 visit after start of treatment documenting taking treatment. Results: A total of 599 women were identified. The median age was 59 years, 58% were non-White, 32% were non-English-speaking, and 35% had Medicaid or no insurance. A total of 506 (84%) were started on hormone therapy. In multivariate regression analysis, the rate of endocrine therapy initiation was associated with higher stage at diagnosis, post-menopausal status, and HER2 negative status. Non-white race, Hispanic/Latino ethnicity, non-English-language, and Medicaid/no insurance were not significantly associated with or without initiation of hormone therapy. 93% of patients started on hormone therapy had evidence of continued treatment, 91% had evidence of continued treatment at 1 year, 75% finished their recommended course of hormone therapy. Conclusion: At an urban safety-net hospital, we do not observe inequities in the initiation of endocrine therapy for breast cancer by race, ethnicity, insurance, or language. Persistence of therapy was similar to nationally reported data. Additional research by hospital type, and granular reasons for non-adherence are warranted. Citation Format: Quinn S. Solfisburg, Brendin R. Beaulieu-Jones, Michael R. Cassidy, Naomi Y. Ko. Initiation and persistence of hormone therapy in endocrine positive breast cancer at an urban safety-net hospital [abstract]. In: Proceedings of the 16th AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2023 Sep 29-Oct 2;Orlando, FL. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2023;32(12 Suppl):Abstract nr A083.