Class of 2014 Abstract / Specific Aims: To assess appropriate use or cessation of metformin therapy in the presence of renal impairment. Methods: A retrospective chart review was conducted on 785 charts of patients at El Rio Community Health Center between June 2011 and December 2012. Eligibility criteria were adults aged 18 years or older with a diagnosis of Type 2 Diabetes Mellitus (DM), a history of metformin therapy, and renal function data. Data was accessed through the electronic medical record (EMR) at El Rio and metformin history, presence of contraindications, renal function, weight, age, gender, and race/ethnicity were collected. Group 1 were patients who were currently taking metformin and Group 2 were patients with a history of taking metformin. Main Results: A larger proportion of patients had renal impairment (eGFR 30-60 ml/min/1.73 m2) in Group 1 than Group 2 (Yates’ p = 0.002). Only one patient in the entire study had severe renal impairment (eGFR < 30 ml/min/1.73 m2). There was a greater proportion of inappropriate cessation in Group 2 than inappropriate use or cessation in Group 1 (Yates’ p < 0.001). Conclusion: Most patients were found to have normal renal function. Group 2 had a greater proportion of inappropriate metformin cessation than inappropriate use or cessation in Group 1.