Cd was measured in the feces, urine, blood, and hair of U.S. inhabitants without known high Cd exposure in Chicago, Illinois, and Dallas, Texas, and in autopsy tissues of accident victims in Dallas. The average intake of Cd in food was estimated to be 13-16 microgram/d and was higher for males than females. The average levels of Cd were 0.59-0.77 microgram/l in urine, 0.09-0.11 microgram per 100 ml in blood, 0.83-1.10 microgram/g in hair, 21 microgram/g in kidney cortex, 1.2 microgram/g in liver, 0.067 microgram/g in muscle, 0.58 microgram/g in pancreas, and 0.040 microgram/g in fat. Hair Cd was higher for males than females. Cd levels increased with age in urine and all tissues and were higher in cigarette smokers than nonsmokers in urine, blood, and all tissues.