Aim: To evaluate fasting serum magnesium in patients with Type-2 diabetes mellitus. Material and Method: This cross-sectional study consisted of patients with type 2 diabetes (n=200) visiting out-patient and in-patient department of medicine at Muzaffarnagar Medical College and Hospital, Muzaffarnagar. A detailed history was taken and clinical examination was done in all patients. Blood investigations and urine examination was carried out. All patients with type 2 diabetes mellitus who meet the inclusion criteria were evaluated, detailed history including age, gender, duration of diabetes, mode of diabetic treatment, duration of diabetes, symptoms suggestive of diabetic retinopathy, diabetic nephropathy and ischemic heart disease and current use of medication, including anti diabetic drugs and antihypertensive drugs, was obtained by a standard interview questionnaire. Clinically, hypomagnesemia may be defined as a serum magnesium level <1.5mg/dl. Magnesium levels were measured by photometric methods. Results: Patients with diabetes of more than 10 years duration had significantly lower serum magnesium levels. Non-proliferative and proliferative diabetic retinopathy was significantly seen in patients with low serum magnesium. Median nerve sensory conduction velocity correlated significantly with serum magnesium. Conclusion: The results of the present study suggest that, and inverse relationship exists between serum magnesium and poor glycemic control, albuminuria, retinopathy and risk of coronary artery disease, respectively.