Adult mallard ducks fed 0, 2, 20, or 200 ppm of cadmium chloride in the diet were sacrificed at 30-day intervals and tissues were analyzed for cadmium. No birds died during the study and body weights did not change. The liver and kidney accumulated the highest levels of cadmium. Tissue residues were significantly correlated in all treatment groups and residues increased with treatment level. Hematocrits and hemoglobin concentrations were normal in all groups throughout the study. Little cadmium accumulated in eggs of laying hens, but egg production was suppressed in the group fed 200 ppm.