To assess the hypothesis that magnesium deficiency is associated with elevated high-sensitivity C-reactive protein (hsCRP) levels.Community-based cross-sectional study.488 apparently healthy children aged 10-13 years were randomly enrolled from Durango, a city in northern Mexico, through two-stage cluster sampling.Serum magnesium and hsCRP levels, lipid profile, glucose and insulin levels.A total of 109 (22.3%) and 101 (20.7%) children had elevated hsCRP concentrations and low serum magnesium levels; among them, 87.1% exhibited both. Children who had both elevated hsCRP levels (2.45 (10.6) mg/l) and hypomagnesemia (1.3 (0.3) mg/dl) exhibit the highest fasting glucose (96.0 (13.9) mg/dl), insulin (13.6 (7.5) microU/ml) and triglycerides (131.5 (43.5) mg/dl) levels as well as the lowest HDL-cholesterol (46.4 (9.0) mg/dl) levels. Adjusted multivariate logistic regression analysis showed a strong association between low serum magnesium and high hsCRP levels (odds ratio 4.1; 95% confidence interval 1.3 to 10.8).Magnesium depletion is independently associated with elevated hsCRP levels, suggesting that hypomagnesemia and low-grade inflammation are interactive risk factors.