Background: Obesity and diabetes mellitus are the most common health problems with both macro- and micro-vascular complications and consequences of end organ damage. The alteration in trace elements could have deleterious effects on the health of the diabetic patients. Magnesium (Mg) is an important factor for enzymes involved in carbohydrate metabolism and good evidence suggests the presence of an important role for hypomagnesaemia in insulin resistance and metabolic control.Objective: To evaluate the relation of hypomagnesaemia with insulin resistance (IR), and glycemic control in obese and non obese diabetic people.Methods: The study included 65 patients with type 2 diabetes mellitus (Type 2 DM) who were all on oral hypoglycemic drugs only. They were divided according to their body mass index (BMI) and the presence or absence urinary protein, into three groups. The results were compared with those of another 52 normal controls grouped on the same bases.Fasting venous blood specimens were aspirated for the measurement of glycated hemoglobin (HbA1c) by A1c variant reader, glucose, urea, creatinine, protein and albumin by routine enzymatic chemical and colorimetric methods, insulin by immuno-enzymometric assay and magnesium by atomic absorption spectrophotometer, while Mg ions and Quicki test (for IR) were estimated by calculations. Morning urine specimens from each subject were examined for the presence of protein by dip Stick.Results: As compared with the healthy controls the study reveals a significant reduction in Quicki test (increased IR) and low serum Mg2+ in all diabetic patients, with the presence of a significant positive correlation between the two parameters. Serum Mg2+ was significantly lower in the normal weight non proteinuric diabetics than the normal weight controls. In diabetic patients the presence of proteinuria caused a further reduction in serum Mg2+. Glycated hemoglobin (HbA1c) negatively correlated with total serum Mg2+ in all diabetics and their controls. Conclusions: Insulin resistance and poor glycemic control are important events associating hypomagnesaemia in type 2 DM. Proteinuria is an additional factor which may aggravate hypomagnesaemia, which involves both ionized and total Mg to the same degree.Key words: type 2 diabetes mellitus, magnesium, Insulin resistance, HbA1C, proteinuria