Abstract Disclosure: A. Deng: None. A. Thirumalai: None. J. Lin: None. M. Weber: None. S. Zuo: None. Continuous glucose monitors (CGMs) have become more accessible for patients with type 2 diabetes mellitus (T2DM) on one insulin injection per day who have either commercial or Medicare plans. However, there are still strict requirements for patients with Washington State Medicaid, creating disparities in diabetes care for vulnerable populations. The aim of this study is to assess the effectiveness and adherence of CGMs in patients with T2DM on Washington State Medicaid plans or institutional financial assistance who are prescribed at least one insulin injection daily, similar to Medicare requirements. This ongoing prospective cohort study enrolled 40 adult patients with T2DM, baseline A1C greater than 7%, and prescribed at least one insulin injection per day from three Harborview Medical Center clinics. Through grant funding, patients were provided with Freestyle Libre 2 CGMs for 6 months. Since this is an ongoing study, we present preliminary results of patients who completed 3 months of CGM use. Effectiveness was measured by the change in A1C from baseline to 3 months after initiation of the CGM (primary outcome) and change in CGM glycemic metrics on ambulatory glucose profile (AGP) from baseline to 3 months after initiation of CGM (secondary outcomes). Assessment of adherence to the CGMs involved tracking the percentage of CGM data captured from the AGP reports recorded at each visit and monitoring dispense history. Twenty patients reached the 3-month follow-up with a median age of 59 years; 60% female, 70% non-English speaking; 45% with Medicaid, and 55% with Harborview Financial Assistance as insurance coverage. Median baseline A1C was 9.2%, duration of diabetes was 10 years, number of diabetes medications was 3, daily insulin injections of 2, and number of blood glucose checks per day was 1. At first CGM download (2 weeks), the median time in range (TIR, glucose 70-180 mg/dL) was 53.5%, coefficient of variation was 35.3% and percent of data captured was 80%. At 3-month follow-up, the median reduction in A1c was –1.2% (IQR -1.8, -0.5). On CGM, the median TIR had increased to 60.5%, coefficient of variation had improved to 31.5% and percent of data captured was 79%. In this ongoing study, preliminary findings show encouraging early evidence of improved glycemic control after CGMs were initiated and patients sustained greater than 70% CGM data captured at 3 months. These results should be interpreted with caution given the small number of participants with results at 3 months. Nonetheless, once the study is complete, the outcomes may be used to inform eligibility requirements for continuous glucose monitors in patients with Washington Medicaid or Harborview Financial Assistance. Presentation: 6/3/2024