The mean serum magnesium level in normal individual was found 1.967 +/- mgm/dl. No significant difference in serum magnesium level was found in various age groups. All diabetic patients, having normal renal function, exhibited hypomagnesemia. The hyperglycemia in these cases was inversely related to hypomagnesemia and its restoration towards normal by insulin therapy restored the normal serum magnesium concentration. These existed in inverse correlationship between serum magnesium and cholesterol (r = -0.56). The hypomagnesemia was the result and not the cause of alterations in the cholesterol metabolism. A positive correlation was observed between blood urea level and serum magnesium (r = +0.7) and it was significant. The magnesium correlated with major diabetic complications too, e.g. micro and macroangiopathies. Thus, serum magnesium can be used for prognostic assessment in diabetic individuals.