The effects of elevated dietary ascorbic acid and iron on copper utilization were examined. Male Sprague-Dawley rats were fed one of two levels of Cu (deficient, 0.42 microgram Cu/g, or adequate, 5.74 micrograms Cu/g), Fe (moderate, 38 micrograms Fe/g or high, 191 micrograms Fe/g), and ascorbic acid (low, 0% or high, 1% of the diet) for 20 d. High Fe decreased (p less than 0.05) Cu absorption only in Cu-deficient rats. High ascorbic acid significantly decreased tissue Cu levels in Cu-adequate rats. High Fe with ascorbic acid caused severe anemia in Cu-deficient rats and decreased plasma ceruloplasmin by 44% in Cu-adequate rats. Cu,Zn-superoxide dismutase activity in erythrocytes was decreased (p less than 0.05) by 14% during Cu deficiency but was not affected by Fe or ascorbic acid. These results may be important to individuals with high intakes of Fe and ascorbic acid.