Background: Magnesium plays an important role in regulating insulin action and secretion. Dietary magnesium deficiency and hypomagnesemia have been associated with inflammation. There is paucity of data regarding this in Indian subjects. Hence, we studied the relation of serum and dietary magnesium with insulin resistance (IR) and inflammatory markers. Methods & Results: We studied the relation of serum high sensitive C-Reactive Protein (hsCRP), interlukin-6 (IL-6) and tumor Necrosis Factor (TNF-α) with cardiovascular risk factors in three hundred coronary artery disease patients. Nutrition assessment was done at the time of recruitment. Patients were evaluated for anthropometry, cardiovascular risk factors, and blood samples were collected. Patients were divided into three groups according to serum magnesium levels; ≤1.6 (Group 1), >1.6–2.6 (Group 2) and: >2.6 mg/dl (Group 3) and into two groups according to recommended dietary allowance (RDA) for magnesium (≤350 mg/day and >350 mg/day). More than half of patients (58.6%) were having hypomagnesemia and 62% were consuming magnesium below RDA. Insulin and IR was significantly higher and insulin sensitivity was significantly lower in group 1 compared to group 2 and 3. Insulin and IR was correlated negatively; and insulin sensitivity was correlated positively with serum magnesium. Similarly inflammatory markers were significantly higher in group1 when compared with group 2 and 3 and they were correlated negatively with serum magnesium. Dietary magnesium was positively correlated with serum magnesium. Insulin and IR were significantly higher and insulin sensitivity was significantly lower in subjects with low RDA for magnesium. Insulin and IR were correlated negatively and sensitivity was correlated positively with dietary magnesium. Inflammatory markers; IL-6, TNF-α, and hs CRP were significantly high in subjects with low RDA for magnesium and were correlated negatively with dietary magnesium. Conclusion: Hypomagnesemia and low dietary magnesium is associated with IR and inflammatory markers in patients with coronary artery disease.