[en] Magnesium serves as a cofactor for various oxidation reactions in the body and helps in glucose transport across cell membrane. Deficiency of magnesium is a common electrolyte abnormality in type 2 diabetic patients and is linked to development of various diabetic complications. This study was conducted to determine the association between low serum magnesium level and type 2 diabetes mellitus presenting at Medical B ward, BBS Hospital Abbottabad. Methods: This descriptive study was conducted over a period of 6 months starting July 1, 2017. One hundred and eighty diagnosed diabetic patients aged at least 40 years, were included in the study. Their serum magnesium level was checked after withdrawing blood under strict aseptic conditions. Fasting and random blood glucose and the level of glycosylated haemoglobin were measured and age, gender, duration of illness were recorded on a proforma. RESULTS: Sixty-one patients (33.89%) had hypomagnesemia. There was no significant association between hypomagnesemia and age and sex of patients (p>0.05). However, hypomagnesemia was found to be significantly associated with the duration of diabetes mellitus among study population (p=0.02). Conclusion: Hypomagnesemia is frequently present in patients with diabetes mellitus and it appears that its prevalence increases with the duration of diabetes mellitus. (author)