Human aortas sampled from populations where there is little advanced atheromatous plaque formation contain higher concentrations of chromium than do aortas from populations in which atheromatosis is prevalent. In the present study serum cholesterol, triacylglycerols, and chromium (Cr3+) concentrations were measured in 32 subjects in whom coronary artery disease was assessed by cineangiography. The distribution of subjects with diseased and normal arteries overlapped below 5.50 microgram of chromium per liter. Only subjects free of coronary artery disease had chromium concentrations greater than or equal to 5.50 microgram/liter. The role of chromium was assessed in the context of the selected risk factors: cholesterol, triacylglycerols, and systolic and diastolic blood pressure. The group with coronary artery disease had significantly lower serum chromium concentrations than did the group with normally patent arteries.