Abstract Disclosure: A.E. Manov: None. A. Donepudi: None. A.S. Dhaliwal: None. J. Tam: None. Y. Badi: None. M. Sharaf: None. R. Haddadin: None. A. Wang: None. K. Mefferd: None. Abstract In this 3-year retrospective observational cohort study, data from fifty-one patients with type 1 or type 2 Diabetes Mellitus (DM), receiving a minimum of 3-to 4 insulin injections per day, and self-monitoring their blood glucose (SMBG) 4-times a day, were derived from our internal medicine residency primary care clinic. The patients were equipped with a Continuous Glucose Monitoring (CGM) device that shared 24-hour glucose data with the clinic. They were assigned to members of our CGM team which included internal medicine or transitional year medical residents who functioned under the supervision of a board-certified endocrinologist. In consultation with our endocrinologist, the resident assessed the patients' glucose management data and adjusted their treatment regimens bi-weekly by calling the patients, and monthly by seeing them in the clinic. The rationale of the study which was confirmatory was to show that in the Internal Medicine Residency clinic in a project governed by the medicine residents, the CGM will lead to improvement in diabetes mellitus control compared to SMBG and this can be done not only in specialized endocrine clinics. The inclusion criteria for selecting the patients were as follows: Age-18-90, diagnosis of Type 1 or type 2 Diabetes Mellitus using 3-4 Injections of Insulin per day +/- other per oral antidiabetic medications and SMBG 4 times a day, HbA1c above 7% while using SMBG, patients who can use the CGM device and receive their primary medical care in our Internal medicine Residency clinic.To assess for differences in A1C, TIR, average blood glucose, percent of time spent in mild hypoglycemia, and percent of time spent in pronounced hypoglycemia, five paired t-tests were conducted. A Bonferroni correction set the new accepted alpha level at 0.01. Significant results from the study include a reduction of HbA1c from 9.9% to 7.6%, average blood glucose decrement from 242 mg/dL to 169 mg/dl, reduction of the incidence of mild hypoglycemia below 70 mg/dl to 54 mg/dl from 4.68% to 0.76% per day, and more pronounced hypoglycemia with glucose less than 54 mg/dl from 3.1% per day to 0.2% per day. We observed a significant increase in the time in the range of blood glucose from 33% to 67% per day. Furthermore, 9.5% of the patients in this study eventually discontinued daily insulin injections and continued treatment with oral diabetic medications with or without the use of injectable GLP-1 receptors once a week.This study affirms that CGM devices significantly improved glycemic control compared to SMBG, supporting its efficacy in optimizing glycemic control in real-world clinical practice. The results imply this can be accomplished in internal medicine residency clinics and not exclusively in specialized endocrine clinics. As far as we know, this is the first study of this kind in a residency clinic in the USA. Presentation: 6/1/2024