Background: Diabetes mellitus (DM) is a worldwide, growing epidemic, with an estimated 415 million adults globally. Patients with diabetes are at increased risk of death and a triad of serious diabetes-specific complications (neuropathy, nephropathy, and retinopathy) and other associated complications. Magnesium is an intracellular cation and co-enzyme for various reactions of glycolytic pathway. Hence, we evaluated serum magnesium level in type 2 DM with and without diabetic retinopathy. Materials and methods: The study is carried out on 40 patients of type 2 DM with retinopathy and 40 patients of type 2 DM without retinopathy. All patients are subjected to the detailed history taking, ocular examination, and investigations like serum magnesium, FBS, PPBS, glycated hemoglobin. Results: The study revealed that there is a significant decrease in serum magnesium level in diabetic patients with retinopathy than without retinopathy (t= -6.297, df= 58 p= <0.001).Similarly Fasting Blood sugar, post prandial blood sugar and duration of diabetes also show significant difference. Conclusion: As magnesium level decreases in patients with type 2 DM, the prevalence of retinopathy increases. Timely monitoring of serum magnesium levels and glycated hemoglobin as well as appropriate interventions would be beneficial in early detection and treatment of diabetic retinopathy.