ABSTRACT Background: Magnesium deficiency at cellular level alters the membrane-bound Na+ K+ AT Pase activity, which is essential for maintenance of sodium and potassium gradients in the transport of glucose. Hypomagnesemia has been linked with defective activity of tyrosine kinase which leads to impaired sensitivity of insulin receptors and exacerbates the insulin resistance among type 2 diabetics. This study was conducted to study serum magnesium levels and HbA1C levels in Type 2 DM patients and to study correlation between serum magnesium levels and HbA1C levels in Type 2 DM patients. Methodology: This study was conducted as cross sectional study on diabetic patient reporting to medicine department during the study period of 18 months. Detailed history was obtained and clinical examination was done. CBC, FBS, PPBS and serum magnesium assessment was done in each patient. Results: The present study was conducted on a total of 125 cases of type 2 diabetes mellitus with mean age of 57.82±10.14 years. Mean HbA1c in diabetic patients was 8.2±1.5% and majority of cases had serum magnesium levels above 1.6 mg/dl. Hypomagnesemia was significantly associated with increase fasting as well as post prandial blood glucose level (p<0.05). We observed a statistically significant very strong negative correlation of serum magnesium levels with serum HbA1c (r=-0.808, p<0.05) i.e. as the HbA1c increased, serum magnesium levels decreased significantly (p<0.05). Conclusions: Hypomagnesemia is one of the common findings in patients with type 2 diabetes mellitus. Poor glycemic control as evidenced from increased FBS, PPBS and HbA1c have been associated with lower serum magnesium levels. As hypomagnesemia is linked with poor glycemic status, it may predict the complications among diabetic patients. It is recommended that serum magnesium levels must be monitored routinely in patients with diabetes as magnesium supplement may help in providing better glycemic control and preventing or delaying the progression of complications.