There are conflicting data on the associations between copper and glycemia, plasma lipids, and atherosclerotic diseases. Copper has both pro-oxidant and antioxidant effects. We performed a cross-sectional analysis to investigate the associations between dietary copper intake and metabolic variables and serum high-sensitivity C-reactive protein (hs-CRP) in asymptomatic subjects from a population-based cohort (n = 1197) and between serum copper concentration and markers of oxidative stress, including plasma nitrotyrosine (NT) and total antioxidant status (TAS), hs-CRP, and metabolic variables in a subgroup of men from this cohort (n = 231). In all subjects, diastolic blood pressure and circulating glucose, uric acid, and total and LDL-cholesterol concentrations significantly decreased, whereas the hs-CRP concentration increased, from the lowest to the highest tertile of copper intake. In the male subgroup, glucose and total and LDL-cholesterol and TAS decreased, whereas hs-CRP and NT concentrations increased from the lowest to the highest tertile of serum copper concentration. In multiple regression models, dietary copper intake was inversely associated with diastolic blood pressure (P = 0.002), fasting glucose (P < 0.001), total cholesterol (P < 0.001), LDL-cholesterol (P < 0.001), and uric acid (P < 0.001) and was directly associated with the hs-CRP concentration (P < 0.001). Serum copper concentrations were inversely associated with glucose (P < 0.001), total cholesterol (P < 0.001), LDL-cholesterol (P < 0.001), and TAS (P < 0.001) and were directly associated with hs-CRP (P < 0.001) and NT concentrations (P < 0.001). Marginal copper deficiency is associated with an unfavorable metabolic pattern, but copper supplementation might not be recommended in view of its association with inflammation and markers of oxidative stress.