Background/Objective Adherence to recommended care remains challenging for patients with breast cancer (BC), particularly those from disadvantaged groups. Although our Center has historically used lay BC navigators to meet with newly diagnosed patients, our team identified the need to improve care for vulnerable cancer patients (pts) through nurse (RN) navigators. This project aimed to investigate adherence to care over two-time intervals, pre and post RN navigators, and investigate the level of out migration (patients who leave our system) of BC patients during the same time. Methods An RN breast oncology navigator started navigating patients and collecting data on Jan 1st, 2018. The RN navigator meets with all newly diagnosed BC pts during clinic and tracks their progression of care, often expediting work up and treatment. A tumor registry audit of refusal of care as coded by “pt or pt guardian refused care” was conducted for two-time intervals: 2016-2017 (pre-RN navigation) and 2018-2019 (post-RN navigation). Out-migration of analytic BC patients was also measured during these time intervals. Results The tables below show total analytic cases and refusal of care rates. Refusal of care rates decreased from 17.8% pre- to 13.2% post-RN navigation. Out-migration was 3.6% for 2016-2017 and 3.6% for 2018-2019. Conclusions Implementation of an RN breast navigator in 2018 trended towards less refusal of care by our patients diagnosed or receiving at least one treatment in our safety net hospital. Refusing chemotherapy and hormonal therapy were treatments that were most impacted by RN breast navigation. RN navigation may enhance compliance through: offering personalized education, dispelling myths of therapy, proactively working with patients when side effects/complications occur, and supporting patients when questions or concerns arise. While there was no difference in “out-migration” to other cancer centers identified during this time interval, the number of patients leaving the system remains low. We plan to continue to track our BC navigated patients and collect patient satisfaction with navigation as a future initiative. This effort was supported by a grant from the Merck Foundation Alliance to Advance Patient-Centered Cancer Care. Citation Format: Christine Rehr, Susan Coples, Zhensheng Wang, Roland Matthews, Pooja Mishra, Jamil Facdol, Rosalyn Garrett, Kimberly Fritz, Sheryl Gabram. The impact of nurse navigation on adherence to care for patients treated for breast cancer in a safety net hospital [abstract]. In: Proceedings of the 2020 San Antonio Breast Cancer Virtual Symposium; 2020 Dec 8-11; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2021;81(4 Suppl):Abstract nr PS7-58.