Introduction: Hypomagnesemia is reported in type 2 diabetes mellitus; magnesium deficiency may play a role in the development of endothelialdysfunction and altered insulin function. Objective: To assess the incidence of hypomagnesemia among patients of type 2 diabetes mellitus and to evaluate the relation of hypomagnesemia to glycemic control and various long-term complications of diabetes mellitus and components of metabolic syndrome. Materials and Methods: Ninety male and female subjects were enrolled in this study, they were classified as: 70 patients with type 2 diabetes as well as 20 control subjects with age more than 35 years. Various diabetic complications were studied. Serum magnesium was assessed. Results: Hypomagnesaemia is prevalent in diabetics and patients having metabolic syndrome hypomagnesaemia in diabetes were associated with poorer glycemic control, retinopathy, nephropathy and neuropathy. High plasma triglycerides, total cholesterol, creatinine, albuminuria HBA1c, fasting and pp blood glucose were independent correlates with low magnesium level. Conclusion: Hypomagnesaemia is prevalent in diabetics and patients having metabolic syndrome.Hypomagnesemia in diabetes was associated with poorer glycemic control, retinopathy, nephropathy, and neuropathy.