Four studies were conducted to determine if the copper requirement is effected by the dietary level of iron and if higher than normal levels of iron are beneficial when high dietary copper levels are fed. A factorial design utilizing 3 levels of copper and 2 levels of iron was used. Diets containing 257 ppm copper when fed to growing pigs tended to produce heavier weights when the pigs were limit-fed. The response was greater when the pigs were full-fed due to increased feed intake. Dietary copper at a level of 257 ppm significantly reduced hemoglobin values and serum iron values, in the absence of supplemental iron. Serum copper levels were significantly increased during early growth by feeding 257 ppm dietary copper. The low copper-high iron diet produced a high serum iron level which would indicate that 7 ppm dietary copper is adequate for normal iron metabolism. Copper accumulated in the liver, kidney and hair, when the pigs were fed the high copper diet. When the diet contained a high level of iron the accumulation of copper in the liver was depressed somewhat in trial IV. The iron content of the spleen, kidney and liver was significantly decreased by the high copper intake which would suggest impaired absorption of iron in the presence of high copper. / Master of Science